Hi Rob, if he is getting fade the I agree 100%, it needs at least higher spec pads. Re the brake fluid definitely (I boiled off a considerable amount of dot3 that was in by mistake in an HS chevette with the brake discs glowing red after thrashing it down pendle hill........ :( .... went to DOT 4 after that.. would be 4.1 now)
I don't know what the modern mintex or high spec pads are like but the ones in the 80's / early 90's were evil until they got to working temps... in this case the larger vents and calipers would be a good choice. I am not a fan of drilled disks at all so would avoid them like the plague due to stress fracturing. Grooved seem better but I never noticed any difference on actual performance providing the rotors and calipers were up to the job. Ducting is certainly a good idea on the freelander ! - We were just mindful that is some cases, such as gravel , dust , off road or 'whites' the ducting can actually fire crap at the discs depending on the run of the pipework, great for tarmac though. :)
Joe

for a standard road pad upgrade id go EBC green stuff pads, work from cold and would stop my old m1 mondeo si on a sixpence with a set of mtec drilled and grooved discs, slight increase in dust but worth it for the stopping power, from experience the groves stop the pad glazing over to a certain extent, and its what i'm intending on fittin to my FL when the time comes, their yellow stuff and red stuff are a higher temp pad which might needs a bit of heat in them to begin with before biting hard
 
Hi Rob, if he is getting fade the I agree 100%, it needs at least higher spec pads. Re the brake fluid definitely (I boiled off a considerable amount of dot3 that was in by mistake in an HS chevette with the brake discs glowing red after thrashing it down pendle hill........ :( .... went to DOT 4 after that.. would be 4.1 now)
I don't know what the modern mintex or high spec pads are like but the ones in the 80's / early 90's were evil until they got to working temps... in this case the larger vents and calipers would be a good choice. I am not a fan of drilled disks at all so would avoid them like the plague due to stress fracturing. Grooved seem better but I never noticed any difference on actual performance providing the rotors and calipers were up to the job. Ducting is certainly a good idea on the freelander ! - We were just mindful that is some cases, such as gravel , dust , off road or 'whites' the ducting can actually fire crap at the discs depending on the run of the pipework, great for tarmac though. :)
Joe

Mintex M171 were horrible until hot. Completely useless on a road car. I always fitted Ferodo "Hard" pads as they gave instant bit from cold.
I don't know if they do different compounds these days. Some investigation is required I feel.
 
Not a fan of drilled discs either. I like grooved discs - largely because they seem to help prevent pad glazing :)
 
Not a fan of drilled discs either. I like grooved discs - largely because they seem to help prevent pad glazing :)
Agreed Rob, grooved are ok, I strongly recommend that others avoid 'drilled' disks like the plague. they are nasty uggy yucky horrible things:rolleyes::( .
Use them in anger and they do tend to stress fracture via the drillings. Designed for bling on the shelf not functionality on the vehicle.

Grooves can be great as they act as a gas expansion and escape area, they also stop the micro particles from abrasion acting as a 'bed of marbles';)

The 1.8 T is a very interesting variation on the K series. You seem well clued up on this genre Lord Rob of the K clan :D .... how reliable are they - I am interested in respect of the technical issues regarding the HGF issues that seem to trouble these units in N/A form. I am not convinced (so far) - purely from a technical standpoint - that the issues with HGF on the N/A K are down to water supply issues (unless of course one has a leak !) :) .... I tend to go with the 'head shimmy' or poor assembly school of thought.. A turbocharged unit should be a good indicator of valid reasons for failures due to the increased stresses and cylinder pressures. The PCP on a forced induction unit can often be 300 - 500 % more depending on application. Interesting stuff..
Joe:)
 
Personally I'm a fan on smooth solid discs without venting, drilling or grooves - mainly because they are cheaper and I don't drive like I stole my car. Having had the experience of brakes dieing on my Disco coming down a hill, I have adjusted my driving style (using the box more) but maybe I should adjust my view on the brakes as well.
 
Agreed Rob, grooved are ok, I strongly recommend that others avoid 'drilled' disks like the plague. they are nasty uggy yucky horrible things:rolleyes::( .
Use them in anger and they do tend to stress fracture via the drillings. Designed for bling on the shelf not functionality on the vehicle.

Grooves can be great as they act as a gas expansion and escape area, they also stop the micro particles from abrasion acting as a 'bed of marbles';)

The 1.8 T is a very interesting variation on the K series. You seem well clued up on this genre Lord Rob of the K clan :D .... how reliable are they - I am interested in respect of the technical issues regarding the HGF issues that seem to trouble these units in N/A form. I am not convinced (so far) - purely from a technical standpoint - that the issues with HGF on the N/A K are down to water supply issues (unless of course one has a leak !) :) .... I tend to go with the 'head shimmy' or poor assembly school of thought.. A turbocharged unit should be a good indicator of valid reasons for failures due to the increased stresses and cylinder pressures. The PCP on a forced induction unit can often be 300 - 500 % more depending on application. Interesting stuff..
Joe:)

A K series turbo engine can be regarded the same as a NASP engine where reliability is concerned Joe. They don't suffer any more from HGF than the normal K series. I actually think they fail slightly less often. The compression ratio is less, so off boost, the coolant temperature rise will be slightly slower. This could well help keep the gasket in better condition for longer;)
 
Hi Joe

Good question regarding the 1.8T - I honestly don't know whether these engines are any more or less likely to suffer HGF than the standard NA lump. My impression is that they are marginally less likely to fail in the ZT and Rover 75 than the standard engine - and part of the reason may be that you don't have to flog the engine so hard (so many engine rpm) to move what is a relatively heavy car from a stand still. [Edit - just noticed Nodge's answer - and agree with his point too!]

IMO one of the key aspects of HGF is the collapse of the coolant return when the engine is cold and the thermostat is shut. The water pump is cam belt driven, so rev the engine hard, it'll generate a significant pressure - sufficient to collapse the by pass pipes and significantly reduce flow: paradoxically, running the water pump harder under these conditions actually reduces flow, and leads to localised overheating of the head.

Improve the low-end torque of these engines, and you're much less likely to flog the engine.

The pressure relief thermostat was introduced to address this problem: the thermostat opens under pressure, alleviating the pressure difference.

Plenty of other problems that are likely to contribute to gasket failure - but this is the one that seems to be the one that the Rover Powertrain engineers reckoned was key.
 
A K series turbo engine can be regarded the same as a NASP engine where reliability is concerned Joe. They don't suffer any more from HGF than the normal K series. I actually think they fail slightly less often. The compression ratio is less, so off boost, the coolant temperature rise will be slightly slower. This could well help keep the gasket in better condition for longer;)
Hi Nodge :)
The static compression ratio is less and also the low rpm dynamic - but that is all. The PCP rises dramatically as boost is applied. IF the units are as reliable as an N/A unit, then this would tend to rule out issues with poor gasket mating in relation to contact area etc. Also - to a certain degree - shimmy and also tend to indicate that issues such as uneven or abnormal spec liner height would tend to be indicative of an effect and not a cause.
There really is a HUGE difference in PCP, I don't necessarily hold to the technical argument of lower compression ratio being helpful I must confess, however, I can understand what you are saying and how an intelligent and aware driver could look after the unit until operating t's and p's were met.
I will look at the pressure bypass Rob mentions.
This would all tend to indicate that the main issues on the K series are thermal stress and differing coefficients of expansion due to uneven cooling in the warm up phase. (NOT be passage issues etc- but by bypass issues in the warm up cycle. In other words 99% of what is written regarding flow bottlenecks and 'so called - and usually totally incorrect 'cavitation' inducing metal restrictive passageways are total ball cocks... It would appear to be '(MAINLY) the issue with the thermal heating bypass circuit.... other issues may well be present - however - they are not at all of primary concern or causality. It is often the case when many many many hundred of pages are written on various forums that most of the hypothetical solutions ans causes are pure BS. also, the market gets bogged down with companies trying to leap on the bandwagon to make a few bucks from a problem that does not exist. The more these charlatan's advertise, the more the folklore grows leading to the same BS / Misleading /Inaccurate 'facts' being passed around as gospel as users try to look for the holy grail.
The sheer LENGTH of the sticky thread here - WHICH SHOULD BE REMOVED IMO. is indicative of this very issue. !

Too many stickys here - the OWUT could be one page and sticky - so could most. It is getting ridiculous to see the new threads for all the totally out of date and misleading sticky threads that are past their sell by date.
Interwesting.......;)
 
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Joe. All the K series HG problems are thermally related. It doesn't suffer from HGF due to cylinder pressures at all. It can make all the power you want in NA or forced and HGF from overloading doesn't happen. It's the way the coolant flows through the system that is main cause, along with the lightweight block, expanding and contracting in cycles as the engine heats up.
The coolant flow through the head is rather hit and miss, with restricted passageways on the gasket face. This is I believe part of the reason for the bypass hose collapses as the revs climb.
There are lots of issues that all combine to make the K series a bit of a lottery were the HG is concerned. It is possible to make HG less common, but even so treated engine still suffer, eventually.

When the K series was first launched in 1.4L form, HG issues simply didn't exist. It wasn't until the unit was redesigned so capacity could be increased that HG problems started to appear.

Sadly the press jumped on this HG issue and sealed Rovers eventual demise. That and a bit of underhand dealings by BMW.
 
Joe. All the K series HG problems are thermally related. It doesn't suffer from HGF due to cylinder pressures at all. It can make all the power you want in NA or forced and HGF from overloading doesn't happen. It's the way the coolant flows through the system that is main cause, along with the lightweight block, expanding and contracting in cycles as the engine heats up.
The coolant flow through the head is rather hit and miss, with restricted passageways on the gasket face. This is I believe part of the reason for the bypass hose collapses as the revs climb.
There are lots of issues that all combine to make the K series a bit of a lottery were the HG is concerned. It is possible to make HG less common, but even so treated engine still suffer, eventually.

When the K series was first launched in 1.4L form, HG issues simply didn't exist. It wasn't until the unit was redesigned so capacity could be increased that HG problems started to appear.

Sadly the press jumped on this HG issue and sealed Rovers eventual demise. That and a bit of underhand dealings by BMW.

Hi Nodge. thanks for the excellent info as always. If it is not a PCP issue, then it is interesting that the 1.4 does not seem to suffer from the same problems.
IF it was a thermal suction issue (with partial collapse of the intake circuit ducting) then I am (at the moment) at a loss to understand how this could be ?
The 1.4 would (IMO) surely 'suffer' the same thermal circuit hose / intake depression / or to look at it another way - atmospheric compression due to a reduced internal pressure differential. Are you saying that it is simply the inability to circulate the coolant to adequately cool the engine ?
The pressure differential in the coolant circuit would be - more or less - the same - apart from the increase in temperature necessitating greater thermal transfer.
If that is the case, then why does the KT not still suffer as the thermal differential due to massively increased PCP cause the system to overload (if - as you say - the flow rate through the system is 'inadequate' or 'marginal' at best ?)
This scenario does not add up to me.The increased PCP and hence massively increased thermal transfer requirements in a super / turbocharged unit would require a very verygood coolant system. BUT - If - as you seem to be eluding to - the system is barely adequate - indeed - just about comfortable - / marginal - then at massively increased PCP, the only logical assumption - in this hypothetical discussion would be that the cooling system is superb ! - and any issue with the warm up phase and pressure differential issues- are 'causing' issues - and not afterwards - !!!!!!! . IF the system is perfectly OK for a massively different PCP hence massively different thermal transfer needs then flow inside the physical structure of the water passages is simply excellent - to say it is not is simply not logical. One cannot have one without the other. :(

IF there is an issue in warm up phase due to recirc' / blockage issues then that is one thing - however - trying to say a coolant system has issues due to passage way issues etc is totally contradictory when you look at the far higher PCP and thermal transfer needs of the T unit.

IMP _ It really DOES NOT add up o_O It really is illogical.
Joe
 
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Hi Nodge. thanks for the excellent info as always. If it is not a PCP issue, then it is interesting that the 1.4 does not seem to suffer from the same problems.
IF it was a thermal suction issue (with partial collapse of the intake circuit ducting) then I am (at the moment) at a loss to understand how this could be ?
The 1.4 would (IMO) surely 'suffer' the same thermal circuit hose / intake depression / or to look at it another way - atmospheric compression due to a reduced internal pressure differential. Are you saying that it is simply the inability to circulate the coolant to adequately cool the engine ?
The pressure differential in the coolant circuit would be - more or less - the same - apart from the increase in temperature necessitating greater thermal transfer.
If that is the case, then why does the KT not still suffer as the thermal differential due to massively increased PCP cause the system to overload (if - as you say - the flow rate through the system is 'inadequate' or 'marginal' at best ?)
This scenario does not add up to me.The increased PCP and hence massively increased thermal transfer requirements in a super / turbocharged unit would require a very verygood coolant system. BUT - If - as you seem to be eluding to - the system is barely adequate - indeed - just about comfortable - / marginal - then at massively increased PCP, the only logical assumption - in this hypothetical discussion would be that the cooling system is superb ! - and any issue with the warm up phase and pressure differential issues- are 'causing' issues - and not afterwards - !!!!!!! . IF the system is perfectly OK for a massively different PCP hence massively different thermal transfer needs then flow inside the physical structure of the water passages is simply excellent - to say it is not is simply not logical. One cannot have one without the other. :(

IF there is an issue in warm up phase due to recirc' / blockage issues then that is one thing - however - trying to say a coolant system has issues due to passage way issues etc is totally contradictory when you look at the far higher PCP and thermal transfer needs of the T unit.

IMP _ It really DOES NOT add up o_O It really is illogical.
Joe

K series cooling issues are complex and many.
The HG doesn't fail at the fire rings. Well it does, but only because the coolant level has dropped. So fire ring failure is a secondary result of coolant loss.
Coolant loss is a result of the breakdown of the elastopolymer bead applied to the stainless steel gasket substrate. The elasto basically delaminates from the stainless steel.
The primary reason for elasto delamination is movement between the stainless and the alloy of the head/ block castings.
This was originally attributed to the head being located to the block with plastic dowels.
Later post 2000 engines were fitted with steel dowels. However gasket delamination still caused HGF, albeit after a few thousand miles more than before. The later thinking was delamination occurred due to expansion differences between the alloy block/ head and the stainless gasket substrate.
The engine has always has cooling system issues. Not with the cooling capacity being to small. The cooling system capacity is overly large for the engine. This coupled with some design issues means the engine doesn't warm up in a nice smooth ramp. What happens is the temperature climbs rapidly from cold to well over the thermostat open temp. The stat opens and coolant flows from the over sized rad, through the stat and quenches the block. This is cooled rapidly due to its low mass and low coolant volume. This cool coolant then hangs around in the block in various stagnant pools, before making it's way through the badly cleaned out coolant ways in the head.
Simultaneously the thermostat has now had time to react to the deluge of cold coolant that passed through it, so it closes again, cutting off the flow from the rad. The engine temperature now sores again and the over hot, quench cycle is repeated, over and over again, until it reaches an equilibrium.
Now let's look at the thermostat it's self. This is the standard stat, not the PRT.
The thermostat is on the return from the rad. It blocks off all flow from the rad, unless it's open.
The thermostat is a conventional wax stat with the normal sensing bulb.
Because the stat is in the return, the bulb has a dedicated flow of coolant directed at it via the bypass circuit. This is the next problem with the design. The pump draws on the thermostat bulb end of the stat housing and the bypass pipe fitted to it.
The bypass is connected to the top of the head and is supposed to circulate the coolant round the engine. However when the engine is revved hard, the pump can outstrip the flow capacity of the bypass circuit, causing the hoses to collapse inwards. This substantial reduction in flow compounds the coolant stagnation in the block and accelerates warm up massively. However because the flow of coolant past the stat bulb has now reduced, it reacts slowly and engine temperature sores once again. Then the stat opens and the block is quenched once again.
This continually cycling engine temperature is what causes the gasket's elastopolymer seal to break down and fail.
If the engine was to warm up in a smooth temperature curve and stay there until shut down, then the HG would last much longer that it actually does.
There are some installation factors that change the working life of the HG. For instance, in the MGF, the bypass circuit is very long. This is why the HGS in those seem to fail at very low distances. Coupled to the fact that sports cars are often driven hard when cold. The HG life is seriously reduced when driven like this.
I think that's it. Hopefully it explains some of the problems with the design.
 
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K series cooling issues are complex and many.
The HG doesn't fail at the fire rings. Well it does, but only because the coolant level has dropped. So fire ring failure is a secondary result of coolant loss.
Coolant loss is a result of the breakdown of the elastopolymer bead applied to the stainless steel gasket substrate. The elasto basically delaminates from the stainless steel.
The primary reason for elasto delamination is movement between the stainless and the alloy of the head/ block castings.
This was originally attributed to the head being located to the block with plastic dowels.
Later post 2000 engines were fitted with steel dowels. However gasket delamination still caused HGF, albeit after a few thousand miles more than before.
The engine has always has cooling system issues. Not with the cooling capacity being to small. The cooling system capacity is overly large for the engine. This coupled with some design issues means the engine doesn't warm up in a nice smooth ramp. What happens is the temperature climbs rapidly from cold to well over the thermostat open temp. The stat opens and coolant flows from the over sized rad, through the stat and quenches the block. This is cooled rapidly due to its low mass and low coolant volume. This cool coolant then hangs around in the block in various stagnant pools, before making it's way through the badly cleaned out coolant ways in the head.
Simultaneously the thermostat has now had time to react to the deluge of cold coolant that passed through it, so it closes again, cutting off the flow from the rad. The engine temperature now sores again and the over hot, quench cycle is repeated, over and over again, until it reaches an equilibrium.
Now let's look at the thermostat it's self. This is the standard stat, not the PRT.
The thermostat is on the return from the rad. It blocks off all flow from the rad, unless it's open.
The thermostat is a conventional wax stat with the normal sensing bulb.
Because the stat is in the return, the bulb has a dedicated flow of coolant directed at it via the bypass circuit. This is the next problem with the design. The pump draws on the thermostat bulb end of the stat housing and the bypass pipe fitted to it.
The bypass is connected to the top of the head and is supposed to circulate the coolant round the engine. However when the engine is revved hard, the pump can outstrip the flow capacity of the bypass circuit, causing the hoses to collapse inwards. This substantial reduction in flow compounds the coolant stagnation in the block and accelerates warm up massively. However because the flow of coolant past the stat bulb has now reduced, it reacts slowly and engine temperature sores once again. Then the stat opens and the block is quenched once again.
This continually cycling engine temperature is what causes the gasket's elastopolymer seal to break down and fail.
If the engine was to warm up in a smooth temperature curve and stay there until shut down, then the HG would last much longer that it actually does.
There are some installation factors that change the working life of the HG. For instance, in the MGF, the bypass circuit is very long. This is why the HGS in those seem to fail at very low distances. Coupled to the fact that sports cars are often driven hard when cold. The HG life is seriously reduced when driven like this.
I think that's it. Hopefully it explains some of the problems with the design.
Thanks for the detailed info
That would certainly explain a lot, of the issues.
Has nobody ever redesigned the external / bypass and stat side of the system to attempt to overcome these issues ?
 
Thanks for the detailed info
That would certainly explain a lot, of the issues.
Has nobody ever redesigned the external / bypass and stat side of the system to attempt to overcome these issues ?

There are a few modifications that have been made over the years.
The latest Payen elastopolymer gasket is supposed to be better at dealing with the continuous expansion related movement.
The MLS is supposed to be more closely thermally matched to the block, reducing failure. However the MLS gasket comes with its own problems.
Rover developed the PRT as a halfway house to moving the stat altogether.
A couple of tuning specialist have made thermostats that fit on the coolant flow from the head. This does eliminate the extreme temperature fluctuation. However the block still has very poor flow through it, giving areas of stagnation. This still results in quite large temperature fluctuation across the block. The actual engine is a brilliant design, unfortunately the way the coolant flows across the block is poor, so it will always be a compromised design.
I'v always thought that it would be possible to install flow control baffles into the block as an after market addition. However the engine would need the liners remove to install such a device. This is well above most people's ability.
Replacing the bypass hoses with rigid pipes would help a bit. This wouldn't resolve the massive temperature fluctuation on warm up or temperature graduation across the block. But would stop the bypass hoses collapsing as the rpms climb.
 
agree with everything you have said. add to that some of the head castings waterways are nearlt closed with casting flash that was not removed and you can have a very poor engine. When I did the gasket on the TF 14 months ago I was going to gring out the waterways but ran out of time. The TF dumped a large amount of water all over the MOT station a couple of months ago and ts looking like time to do it all again. Will not be using a multi layered gasket next time and I have bought a new thermostat. you can see the water ways n mine were not bad, I have seen pictures where they were nearly completely closed off. I want to circle the holes but do not know how to. apologies
image.jpeg
 
agree with everything you have said. add to that some of the head castings waterways are nearlt closed with casting flash that was not removed and you can have a very poor engine. When I did the gasket on the TF 14 months ago I was going to gring out the waterways but ran out of time. The TF dumped a large amount of water all over the MOT station a couple of months ago and ts looking like time to do it all again. Will not be using a multi layered gasket next time and I have bought a new thermostat. you can see the water ways n mine were not bad, I have seen pictures where they were nearly completely closed off. I want to circle the holes but do not know how to. apologiesView attachment 105776
Hope this helps -(ringed the main culprits that are visible) and yes, they are terribly finished - I would definitely get the die grinder on those ! - that is crazy. :(
Joe :)
waterways.jpeg
 
Here's an example I did a while ago.
This is an early VVC head with similarly badly cleaned out coolant passages.
The later head has additional coolant ways between the valves. These are there to help reduced cooling issues around the valves.
Screenshot_20160801-133851.png
 
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That is terrible ! - really bad QC..
The interesting thing is that how much difference does the cleaned out flashing on the coolant pathways actually make ?
Again, this is a clue to the overall functionality -or not ...................... ?
 
Yep, seens pics like that before, that head is not going to get good coolant flow, at least mone had holes, some of yours are completely blocked.
Will be doing my engine in the next couple of months and will using the die grinder this time.
 
That is terrible ! - really bad QC..
The interesting thing is that how much difference does the cleaned out flashing on the coolant pathways actually make ?
Again, this is a clue to the overall functionality -or not ...................... ?
It's difficult to be 100% sure. But it would follow that cleaning up the passageways to the casting marks would make the coolant flow as the designers intended. All the K's that I've done HG work on were similarly affected by casting flash, blocking ways like those pictured.
Who knows. No blocked coolant ways, could mean no HGF.
We don't rip heads of perfectly working engines to find out, do we?
 
Nodge, Does the KV6 suffer from the same issue with flash in the cooling passages.
No issue here, just curious as my V6 runs with the temp guage pegged in the middle.

BTW: I had excellent results using one of the N-Series head gaskets on a 1.8 after an MLS gasket failed in a matter of weeks.
 

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