Datatek
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A second hand head from an Omega is not that expensive
Overheat - Am I missing something
- Thread starter timh1970
- Start date
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I have been doing a bit of digging and (please correct me if I am wrong) it appears that the head was modified on the 99MY model. I guess that there was more to this modification than just the addition of a thermostatic switch.
I have a sneaking suspicion that my ecu is out of a 99MY even though the engine is pre 99. Also everybody says that they are sluggish, but mine just isn't (yeah you aren't going to win any races with it, but I wouldn't describe it as sluggish; and I am a bit lead footed).
Did the 99MY have a bit more power than the pre 99 model?
My thinking is that if the ecu was remapped on the 99MY and the head was modified to cope with the extra heat that would obviously be generated by the extra power then I have no chance of stopping this unless I put an old ecu in the car. It would make perfect sense with the way it is behaving as it cools down just as fast as it heats up when the load is reduced.
I have a sneaking suspicion that my ecu is out of a 99MY even though the engine is pre 99. Also everybody says that they are sluggish, but mine just isn't (yeah you aren't going to win any races with it, but I wouldn't describe it as sluggish; and I am a bit lead footed).
Did the 99MY have a bit more power than the pre 99 model?
My thinking is that if the ecu was remapped on the 99MY and the head was modified to cope with the extra heat that would obviously be generated by the extra power then I have no chance of stopping this unless I put an old ecu in the car. It would make perfect sense with the way it is behaving as it cools down just as fast as it heats up when the load is reduced.
Datatek
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Pre and post 99 EDC's have different connectors so cannot be swapped.
Power of all models is similar. Post 98/99 a MAF and EGR was fitted along with the different EDC and an overheat sensor. I'm not aware of any head mods and in other applications the power was higher then the P38 application.
Thanks for clarifying that; it was just a passing thought.
So I still haven't took the head off yet, although I have had the rocker cover off and cleaned out the mesh filter for the oil catcher.
This is just a bit of info for people reading this thread in the hope of resolving their overheat problem:
If you have a nanocom and set it to instruments it will report the temperature that is measured by the sensor that reports to the engine ecu (the one with the green socket towards the back of the engine). The front one (sometimes blue with 2 pins and sometimes orange with a single pin) sends to the temperature gauge on the instrument panel.
The 2 wires from the ecu sensor go to pins 13 and 53 on the single plug edc ecu. I have no idea if the engine ecu reports to the becm and that has any effect on the gauge but I cannot see why it would.
The green socketed sensors do not seem to be very accurate at low temperatures as I have put 3 in now and all have reported -1 degree when cold (There is nothing wrong with the wiring to the ecu and with both gauges operating independently I doubt that this is the cause of the problem).
The engine oil cooler (which is another aftermarket piece of junk) is looking highly suspect though as when I took it off I discovered that I could move the cooling fins (which is bound to affect conductivity and subsequently cooling) - going to fit an oem one tomorrow so here's hoping! In any event it is knackered and will need replacing before I go to the effort of changing the head.
I have fitted a mod to the car to make the cooling fans come on using a thermostatic fan switch that BMW use for the 525d's etc. in the back of the cylinder head. (The same one that I think is used for the 99MY mod). This is an easy mod but would be a whole hell of a lot easier if the switch was normally open instead of normally closed.
This is just a bit of info for people reading this thread in the hope of resolving their overheat problem:
If you have a nanocom and set it to instruments it will report the temperature that is measured by the sensor that reports to the engine ecu (the one with the green socket towards the back of the engine). The front one (sometimes blue with 2 pins and sometimes orange with a single pin) sends to the temperature gauge on the instrument panel.
The 2 wires from the ecu sensor go to pins 13 and 53 on the single plug edc ecu. I have no idea if the engine ecu reports to the becm and that has any effect on the gauge but I cannot see why it would.
The green socketed sensors do not seem to be very accurate at low temperatures as I have put 3 in now and all have reported -1 degree when cold (There is nothing wrong with the wiring to the ecu and with both gauges operating independently I doubt that this is the cause of the problem).
The engine oil cooler (which is another aftermarket piece of junk) is looking highly suspect though as when I took it off I discovered that I could move the cooling fins (which is bound to affect conductivity and subsequently cooling) - going to fit an oem one tomorrow so here's hoping! In any event it is knackered and will need replacing before I go to the effort of changing the head.
I have fitted a mod to the car to make the cooling fans come on using a thermostatic fan switch that BMW use for the 525d's etc. in the back of the cylinder head. (The same one that I think is used for the 99MY mod). This is an easy mod but would be a whole hell of a lot easier if the switch was normally open instead of normally closed.
i used data's fan mod and this stat: Capillary Thermostat Cooling Radiator Fan Control Unit UNIVERSAL FITTING | eBay
Located the stat in the empty engine ecu housing behind battery, sensor on top hose
for back up only, viscous fan still main cooling
Located the stat in the empty engine ecu housing behind battery, sensor on top hose
for back up only, viscous fan still main cooling
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Yes I am keeping my viscous; Glad you mentioned the spare space in the ecu housing, that is a perfect place to stick my relay
Oh come on! This car is really taking the p!55 out of me now: One thing that I have discovered since owning this car is that range rover after market parts are quite possibly the worst parts that I have ever come across; but you can't go wrong with a pipe that goes from the engine to the oil cooler; right? erm... Wrong! Just bought an aftermarket pipe the rubber part of it is too short so it is not flexible enough to allow the pipe to reach between the two.
Arrrrrrrrrgh!!!!!!!!!!!!! I hate this damned car, but I am not going to let the 8a5tard thing defeat me. (I know, I know; it's got me and I should let it go, but I just refuse to give it the pleasure).
Arrrrrrrrrgh!!!!!!!!!!!!! I hate this damned car, but I am not going to let the 8a5tard thing defeat me. (I know, I know; it's got me and I should let it go, but I just refuse to give it the pleasure).
tomcat59alan
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Use the pipe to give it a thrashing a la John Cleese
I will, once I retrieve it from the suppliers 4R5E
tomcat59alan
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I will, once I retrieve it from the suppliers 4R5E
Nasty, wouldn't want to touch it knowing where it's been.
Have you taken the old pipe off because they have a habit of stripping the threads off the oil cooler? 
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Engine ECU changed in 1998 for EGR it was not changed again up to end of production. MSB106370 is the only unit available for the EGR engine as far as i can see.
luckymark
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have you changed the oil recently? because my oil burner was running slightly above the center point on the gauge when under load or going up steep hills, i changed the oil and she now runs just below the center of the gauge in the same conditions
My car is a 97 with no egr that has the ecu with the single plug on it. According to rave the other ecu has 2 plugs on it. There is no egr and no plastic manifold on my car. I have to follow the circuit diagram for the 99 car so it looks like another bit that has been replaced (possibly with the engine at some point).
I am get the feeling that I am the proud owner of the equivalent of Frankenstein's monster. It certainly behaves like that.
Nasty, wouldn't want to touch it knowing where it's been.
Yes, I bought a new oil cooler with a view to fitting it but when I took the pipe off the old one, it left most of the thread in the nut so with no means to get the nut off and clean it out I had to buy a new pipe. I though I might as well buy a pair of them and thought that nobody could fcuk up a pipe not even the aftermarket Range Rover artists but unfortunately I was only half right. The long one was fine, but the short one was... erm... too short.
I nearly bought another P38 yesterday for parts, it was on ebay and went for 600 quid in Chorley which is fairly near to me, but I missed it. Perhaps it was for the best.
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Get a diagram for your car, wiring is very different in many aspects. I cannot think that your car has a EGR engine loom. Does your car have a IAT sensor in the manifold that is coupled up. There is no provision for that in the later loom.
Yes, the IAT sensor is coupled up. Following electrical diagrams is one of my stronger points, so thankfully I can get by with what I have. Mine is 97 so I guess there must have been some sort of X over period.
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The new ECU was introduced for MY 1998 and the introduction of EGR. A MAF was introduced which replaced the IAT sensor. IAT became a low preset to ensure EGR operation. MAF to tell the ECU how much EGR was being applied. Other than a new number four injector everything else remained the same. For MY 1999 the extra sensor was added to bring on aircon fans on over heat and the fuse box layout was changed many fuses changing function. So getting a wiring diagram for your year is a really good idea. Reading a 1999 diagram and applying it to your car is like working on a heater and following the instructions for a fridge.
Well miracles do happen; I've finally got it right and although it was actually several problems it all boils down to one thing.
AFTERMARKET JUNK!!!!!
Aftermarket thermostat - JUNK
Aftermarket pump - JUNK
Aftermarket engine oil cooler - JUNK
Aftermarket radiator - JUST ABOUT OK ish but it is going as soon as I can afford a genuine one.
The thermostat added about 2 degrees to the average temperature, the pump 3 degrees the oil cooler 1 degree and the rad took about 2 degrees off compared to a bunged up genuine one.
It is the pump and the stat that made the biggest difference though. The aftermarket pump that I bought has less vanes in it than the original one and this makes a hell of a difference to the circulation. The design of the vanes is less than convincing compared to the genuine one. The genuine one is plastic and has a bigger drive shaft whereas the aftermarket one is metal so at first appears to be of better quality. Rumor has it that the plastic ones come off the shaft (I don't know whether this is true or not, but at least they work properly when they are on it).
AFTERMARKET JUNK!!!!!
Aftermarket thermostat - JUNK
Aftermarket pump - JUNK
Aftermarket engine oil cooler - JUNK
Aftermarket radiator - JUST ABOUT OK ish but it is going as soon as I can afford a genuine one.
The thermostat added about 2 degrees to the average temperature, the pump 3 degrees the oil cooler 1 degree and the rad took about 2 degrees off compared to a bunged up genuine one.
It is the pump and the stat that made the biggest difference though. The aftermarket pump that I bought has less vanes in it than the original one and this makes a hell of a difference to the circulation. The design of the vanes is less than convincing compared to the genuine one. The genuine one is plastic and has a bigger drive shaft whereas the aftermarket one is metal so at first appears to be of better quality. Rumor has it that the plastic ones come off the shaft (I don't know whether this is true or not, but at least they work properly when they are on it).
Datatek
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Over time, the plastic one's either come loose on the shaft of break up, should be OK for at leadst 50K though. Interesting about the impeller though.
