Disco 2 Low power 300tdi

[Not176]

Hi all I’m new to the site! my 300TDI overheated badly (head gasket) so I replaced the head. Now it’s low on power and smokes black the turbo is ok, the intercooler is not blocked and the air filter is new. It starts fine and idles well but I suspect it might have damaged the injectors but I don’t know if this could cause low power, any advice would be very very welcome, sorry if this has been asked before
N

 

[resto_d1]

Was the block checked for flatness, did you install the right HG (hole reference), did you put original head back on, was that also checked for flatness and cracking, particularly around glowplugs? Why did it overheat?

 

[Not176]

Was the block checked for flatness, did you install the right HG (hole reference), did you put original head back on, was that also checked for flatness and cracking, particularly around glowplugs? Why did it overheat?

Thanks Resto, the overheat was caused by the cylinder head gasket failing and boiling the coolant at the same time the temp sensor failed so I didn’t know till I could smell it hot. The block was checked and is flat I installed a brand new head, valves, pushrods, head bolts and the correct gasket. It starts fine and runs but there’s no power so I thought it was the turbo but there appears to be plenty of pressure there when you rev the engine. My knowledge of injectors is limited so I don’t know if faulty injectors, from a over heat could cause the issue I’m seeing
Thanks for the reply
N

 

[resto_d1]

Have you a boost gauge fitted? Could well be a hose or something collapsing on itself?

 

[resto_d1]

Also, it could be other way round - the overheat caused the HG failure so I’d be going through cooling system with fine tooth comb. If water pump or even p gasket fails it can drop enough to get it too hot.
If you’ve spent a load of cash on head etc I’d definitely look at a low coolant alarm. I had one in mine and will in my rebuild.

 

[Not176]

Thanks everyone for taking the time to reply what I didn’t mention was that the reason the HG initially failed was because I had it done by a cowboy because I didn’t have time he then did a runner with my cash and he left 3 head bolts loose when I inspected it I could remove them with my fingers. I replaced the head myself so I’m fairy sure the coolant system was ok. I haven’t fitted a boost gauge I could do this and I suppose it would prove the turbo?
N

 

[Anaconda]

Just to clarify.
1. The head gasket was changed for some reason, was it driving correctly previously?
2. A cowboy changed the head gasket and it over heated, was it driving correctly between head gasket change and over heating?
3. You then fitted a new head and gasket etc?
4. Starts fine, tick over is good, doesn't over heat but down on power?
Presumably you have double checked all your work?
Boost pipe going to the injection pump? (I presume it's similar to the 200tdi)
Injector refurb isn't a massive amount of money, although receiving non leaking ones back is a different story.

 

[Not176]

Ok
1 it’s done 190K on the original HG
2 I drove it for the first time after it was repaired and I didn’t get 50 miles before it over heated, I didn’t notice till it failed because he failed to connect the temp sender unit plugs and the engine smelled hot really hot
3 Starts fine ticks over well it’s drivable but low on power as for over heating I haven’t managed to get the temp gauge to work since it over heated and when I say overheated I mean it melted the plug on the temp sensor on the top of the head, ( I haven’t been able to find a replacement for that yet) but I’m only driving it short distances while I try and sort it out. As for double checking everything I only know what I know, when I inspected the bores there was some light scoring but it’s done 190K. I assumed that if it starts from cold first turn then the compression is good but that’s an assumption.
4 Boost pipe going to the injector pump?? Now then not sure about that I only rebuilt what I assumed was damaged I need to check that one out and if anyone knows where I can get a plug (part of the loom) that connects to the temp sender in the head than that would be great
You guys are all amazing, really appreciate the discussion
N

 

[resto_d1]

Jesus wept. Won’t let him touch your motor again will you!!

 

[resto_d1]

Just my paranoid way, especially if you’ve spent a fortune on, get a water temp gauge fitted, get a boost gauge and get a low coolant alarm. Some people fit the temp sensor where you’ve lost yours on the old head rather than relying on the gauge in the dash. You won’t know it’s too hot until too late!!
Did you fit an AMC head? It’s either going to be an issue with air or fuel Isn’t it. I guess if it’s got silly hot it could be injectors. At that mileage they’d be due a tune up anyway.
Also, your turbo hoses will be towards end of life.
I thinks it’s daft to spend money on it yet not upgrade and replace hoses, pump, stat etc.

 

[Anaconda]

Surely the coolant temp sensor is in the thermostat housing, is it not?

300Tdi Head Temperature Probe Thread Adaptor

300Tdi Tmperator Probe adapter for adapting the EGR sensor to a coolant sensor

fourby.co.uk

 

[resto_d1]

Surely the coolant temp sensor is in the thermostat housing, is it not?

300Tdi Head Temperature Probe Thread Adaptor

300Tdi Tmperator Probe adapter for adapting the EGR sensor to a coolant sensor

fourby.co.uk

yeah but also one at back of head with a blue socket on it

EDIT - seems that one’s originally egr though

 

[Anaconda]

Pardon our interruption...

Is that a suitable plug for the sensor?

 

[Not176]

Hi all thanks for all the valuable help, i'm going to start with the injectors I think, ill get them out and tested this week, once I have that then im going to heed the advice regarding a secondary cooling sensor, low coolant alarm and turbo boost gauge. I am sure ill get to the bottom of it eventually. Its not my main runner but i use it off road quite a bit so I need to sort it out really, thanks again everyone for all your help
N

 

[Anaconda]

Keep us updated, hopefully you will find the answer and in turn it will help someone else.

 

[resto_d1]

Definitely worth sorting, especially if you’ve already spent out.
The low coolant alarm can be done cheaper but I’m not the best with the wiring so I got one off eBay.
The blue sensor, as per anaconda link is actually egr - that to me says that your dash gauge reads off the one in thermostat housing.
The link he posted, allows you to use a probe for head temp. I bought a durite gauge and tapped the top bleed screw in the housing so I could read coolant temp and will be doing same again on my new build.
I don’t know if you’ve checked but there’s diesel bob and bob Beckett for your injectors etc.
Just incase (not telling you how to suck eggs) but if you also doing the coolant side, you’ll want the pro flow G part waterpump and a wax stat. Be sure to do p-gasket too. I bought stoney racing or something like that and re-hosed the lot! Again, eBay seller.
I’m ranting but feel free to PM if you want parts advice as I’ve bought fair few

 

[Not176]

Definitely worth sorting, especially if you’ve already spent out.
The low coolant alarm can be done cheaper but I’m not the best with the wiring so I got one off eBay.
The blue sensor, as per anaconda link is actually egr - that to me says that your dash gauge reads off the one in thermostat housing.
The link he posted, allows you to use a probe for head temp. I bought a durite gauge and tapped the top bleed screw in the housing so I could read coolant temp and will be doing same again on my new build.
I don’t know if you’ve checked but there’s diesel bob and bob Beckett for your injectors etc.
Just incase (not telling you how to suck eggs) but if you also doing the coolant side, you’ll want the pro flow G part waterpump and a wax stat. Be sure to do p-gasket too. I bought stoney racing or something like that and re-hosed the lot! Again, eBay seller.
I’m ranting but feel free to PM if you want parts advice as I’ve bought fair few

Thanks again, i didn't know that the blue head sensor was for the EGR my coolant sensor doesn't work so ill utilise that being as my EGR is in the bin, ill let you know how I get on thanks
N

 

[resto_d1]

Thanks again, i didn't know that the blue head sensor was for the EGR my coolant sensor doesn't work so ill utilise that being as my EGR is in the bin, ill let you know how I get on thanks
N

Fairly sure it is. Didn’t realise it either until I read the fourby link and now makes sense. Mine was never plugged in - previous chap used it as a tippex pot for marking head bolts

 

[resto_d1]

Also, if you don’t want the gauges everywhere - fourby do a clock that you can wire the temp sensor into I’m pretty sure you can run both egr and coolant temp from it.