Wonder if anyone can help ?

I suspect the words head and gasket may figure - I'm just hoping not !

So, 2007 L322 3.6 TDV8 - 268 K Miles, yes, I know, the moon and on its way back.

From a cold start the coolant system seems to pressure up really quickly, top hose goes solid within a minute or two. If I remove coolant cap after a couple of minutes cold coolant blasts out. If I drive it, it will eventually overheat normally forcing past the coolant cap.

No ODB Codes and the engine runs smoothly etc. No smoke/steam/coolant from the exhaust. No smell of exhaust in the coolant (chemical test kit arriving soon).

I think the chemical test may well confirm my suspicions that the coolant system is being pressurised from the engine and i'm assuming a gasket and/or warped head might be the culprit ? I know the TDV8 can suffer badly from airlocks i the cooling system but I think I'm hoping against hope ?

Thanks in advance.

Have you checked the other coolant pipes to see if heat is getting into them all, just a thought that you might have a blockage somewhere in the system. Is the radiator the same heat all over?

Thanks for the prompt reply.

Very good point. I haven't checked - I'll go have a look.

Do these have an egr cooler? Cheers

James

Er, I’m no expert but I believe they do. Where might you be going with your thinking ?

Sniff test is the best way forward Nick...

I'm making a bit of headway. Got the chemical sniff test, sent it back as they sent me blue liquid type. Tested it today and the red liquid went yellow inside a couple of minutes.

So I think this proves I'm getting combustion gases into the coolant.

I've decided to give Steel Seal a try as for £80 if it works its magic then it has to be better than a head gasket change on a 286K mile engine.

For a pressurised coolant issue the Steel Seal instructions suggest I should disconnect each injector in turn to try and establish which cylinder is pressurising the coolant. Then run the sealant though with that cylinder disconnected. I see the logic as the sealant will have trouble getting to the site if pressurised gases are flowing into the coolant.

So, does all of this sound like a plan ? and does anyone know how easy it is to disconnect each injector in turn ?

Many thanks

Have a look at this guys videos as he has done what you want to do sir...

Thanks Craig,

Seems from the vid he has a right pile of doo-doo under that bonnet. Mine's nowhere near as bad so, fingers crossed !!

Absolutely but it worked on his which was the main point 👍

So, 2 bottles of Steel Seal later and things are much better but still not right !

Its stopped boiling over when cold and hose pressures are better but it still wants to overheat under normal driving.

Just got back from a 10 mile run and noticed its close to over heating - Temp gauge is normal and central but car drops out of cruise (which has always been a tell tale that its about to overheat).

Nursed it home for the last mile and noticed the following.

Top hose is very hot as is top of radiator. Entire auxiliary radiator and pipes are stone cold. - is this normal ?
Isn't the aux radiator flow controlled by the thermostat (rather than ECU) ? and if so, shouldn't it also be very hot ?

Is a thermostat change in order or am I missing something ?

Thanks in advance

That sounds like a water pump issue, change the water pump and the thermostat. BMW i3 Electric Car
2012 Full Fat RR 4.4 TDV8 (now gone)
2006 VW Touareg 3.0 TDi V6

.. BMW i3 Electric Car
2012 Full Fat RR 4.4 TDV8 (now gone)
2006 VW Touareg 3.0 TDi V6

So i'm still going with this one.

Stat and housing changed - no better. So I think the pump next, noticed when bleeding the system from the fuel cooler pipe as per RR manual the output of water is very haphazard - I would expect a steady stream but its nothing like a steady stream. No visible signs of failure at water pump but not much else left to change now !
So unless anyone else has some genuine pearls of wisdom to offer ...........

My 2c just quickly...
I thought you said it was getting combustion gas into the coolant?


You need to rectify that... No two ways about it. If it's been pressurized from a cylinder (particularly in an engine running 25psi boost) the coolant has to leak out somewhere.

Head gasket time... You sorta said it's not worth doing head gaskets yet because the engine has done some near 300k ks but to my way of thinking that means even more so perhaps it's time to do them and I'd want to do them before something more severe arises from overheating

There are two egr coolers but I can't see them pressurizing the cooling system.. in fact I think the reverse would happen

I'll feel my hoses top and bottom today after a run but there has to be a temp difference there otherwise the radiator is not doing it's job.. which is irrelevant anyway if you have a combustion leak which needs fixing first



Dave 2010 3.6TDV8 Autobiography
D4 Bullbar, Bas remap, Egr deleted (blanked & via remap) , Cold air intake, Turbo back exhaust, Provent 200 catch can, Banks idash gauge, 255/60/R20

GAP Diagnostics

Past - 02 & 03 TD6 And an 1984 Classic