It has to be something fairly simple Matt as already alluded too, the cooling system is not that complex so if all other tests are coming back fine then it would suggest poor flow.

It has to be said Matt has suffered some very bad luck by all accounts Rudi, but for every troublesome Coupe like this there are twenty good ones just doing the business with good quality maintenance.

^ Agreed.

Matt sounds like a partial blockage, i'll buy you a beer mate when I see you.

I'm going to whip the radiator off tonight and see if there is anything obvious. But thanks for the support chaps

Chin up Matt, I would take off a pipe and stick a hose in the tank and flush the rad... Then flush the engine doing the same.. Just catch the water in a bucket so you can see if any thing come out.

It's got to be a silly block sone where!!!

Cheers mate, i'll give it a go.

Call me if you need a hand!!

For me the really positive thing here is that the vultures haven't started circling in case you decide to strip it back to standard.

By a process of elimination, there can't be much else to check out can there?

You've got a lot of support behind you Matt including some very knowledgeable "experts" but I can't begin to understand / appreciate your pain and frustration.

Really hope that you find the problem and that it's a cheap fix to sort.

Well, I stripped the radiator off tonight, and it is like new really.

I also ran water through the coolant system and checked coolant hoses and everything is fine.

I found no "bits" of debris or anything which could cause a blockage.

So, heres my theory;




Circled in the above photo is the route which my braided oil cooler takes. As can be seen it runs right across the 3" downpipe. It is covered in heat wrap and there is a heat shield there too, but when on boost for a long period, that downpipe is going to be circa 900 degrees hot.

What are the chances of the oil getting soooo hot, it's having an adverse affect on the engine/coolant and boiling it up??

This is the only thing left to try really.

Opinions please

I doubt it to be honest, the water would only be exposed to that heat source for a fraction of a second as it rushes by, and couldnt be the difference between boiling up and staying normal. If it did have an effect it would be to raise the temperature by a couple of degrees overall but it would still stay stable.

Simply running water through the pipes is no good, you need to replicate the high pressure and high flow rate that will be happening on track, and you cant check the insides of all the pipes without taking them all off and poking stuff through or cutting them open. I just hope the blockage is not in the waterways of the engine block itself, that could be a tricky one.

As i dont have an oil temperature gauge in the car (it's a really handy voltmeter ) i have no idea what kind of temps the oil is seeing.

My theory was that if the oil is heating the block, that may in turn heat the coolant to above the tolerances which it would normally work within, i.e outside the tested coolant system parameters

Matt I haven't had time to read all of this thread but when the head was off last was it pressure tested?

Yeah the head has been pressure tested. All the cylinders were pressure tested to nearly twice as much as what it would normally see. It's also been sniffer tested, the coolant is fine, there's no smoke, so i'm reasonably confident it's not the head.

Saying that i suppose there is a chance it could have become pourous or a minute crack which only shows when it's red hot, but i think its doubtful.

It's just the way you describe the issue is only apparent when either on the track or after long boost periods, it gives me the impression of a cracked head.

Ah gotcha now, I think that's even less likely though. When everything heats up the oil is always the last thing to get hot, and the last thing to cool down afterwards. It basically follows the coolant temperature by about 5 minutes. For the oil to do that it would have to reach such high temperatures that it would be far too thin to do any lubricating... IMHO.

Totally agree with you Matt, and with you Joe, but all other avenues have now been explored.

My plan is to fit an oil temp gauge, hoon around like a mad man and see if the oil is getting hotter than it should. If it stays normal then god knows

If the oil was going up to 130C+ you would definitely see a big drop in oil pressure. The cooling system is where you need to be focussing your attention.

Tell you what, I may be breaking a very nice Coupe at the end of the month, was going to fix it up with new big end bearings but it looks like I'll be buying my old Coupe back instead.

You can have the head, the thermostat, the water rail, and all the coolant pipes for free, which should be a major step in the process of elimination.

That is very kind of you Matthew, thankyou very much.

When on high revs, actual oil pressure is around 11bar (ish i think) So the oil could heat and thin down a lot before any oil pressure drop was noticed on the gauge.

Hmmmm, saying that i had 1.5 bar oil pressure whilst the car was overheating, so perhaps that does eliminate that, but i'm using some gulf competition oil which is rated for engine with over 1000bhp

Hope you find the reason for this issue Matt , would be a shame to finish this ownership

It would Joe, although the car is a little tatty on the outside it drives superbly and has been very well looked after.

I'm just a little lost as to what to look for.

Do i really want to fork out for a head swap just on the off chance? - i dont know if i do

Matt, when you flushed the engine, how did you do it?

Also the oil temp will be near 100 degrees or so to get 1.5bar on idle.

Could it be the turbo causing a block when it gets bloody hot??

Sorry Marco, but what do you mean by "glided the engine"?

I dont think it can be the turbo, as it has a seperate feed from the water jacket and then leads back to the bottom of the radiator, so even if it blocked up then the water would still circulate round the engine. ( i may be wrong)

edit: just seen that you meant flush the engine.

I removed the rad completely, put hose pipe into expanison tank and sealed round it, then just flushed with water. The expansion tank was filling faster than it was coming out, but i guess this will be vecause the pump is not spinning??

All you've done there is prove that it's not completely blocked, but if it was the engine would be toast anyway. It must be partially blocked somewhere which is only causing a problem at high revs / high flow rate.

how old is the stat,might be stuck half way

Brand new stat. Will start taking water pipes off tonight.

You had a new water pump i think Matt.What about sealent gunk or anything you can think off stuck part way across a flow way.
I also think the turbo cooling needs looking at as said by Marco.

Must be something lying around somewhere that gets in the way of the coolant, maybe even only when the coolant gets a bit hotter (on track) and makes whatever is in there a bit softer. Can't you install some sort of flow meter in the circuit somewhere?

http://www.flowmeters.com/
http://www.ftimeters.com/pdfs/application_notes/an69620_automotive_racing_engines_mag_meter.pdf

Other than that, if you check by using an garden hose, run it backwards through the system.

Matt... when i flushed mine, the tank was just rushing water straight round the engine and out of the pipe...

i think you have a block some where mate...

problem you will have is the thermostat will not open untill its upto temp...
you need to some how get the water straight into the engine.. not sure how i did mine.. it was well over 2 years ago now.

but what i do know is with a rad pipe off the water should flow out pritty quickly..

crazy idea...

why not put some thing in the coolant system to clear blockages... like Mr Muscle??

thinking about it, i doubt the turbo would be at fault.

DO NOT PUT MR MUSCLE or other household pipe cleaning fluids into an engine, unless you want it to dissolve...

Matt - if you really need to know your oil temp you can stick one of these on the sump:

http://www.temperature-indicators.co.uk/acatalog/Industrial_10_Level_Indicators.html

I've used the mocal equivalent before and they work fine.

I really dont think the issue is with your oil temps though - look to the water system.