Pressurising Coolant.

Hi all, My discovery has been behaving itself since i purchased it, that is until the other day when i was towing my Ifor with a range rover on it! i noticed the next day i had pressure in the cooling system and the coolant level had gone down about 5mm. Anyway i suspected the head gasket so ordered a sniffer kit and tested it, and after about 5 mins of idling the fluid changed colour indicating combustion gasses in the cooling system.
It doesn't pressurise under normal driving but does when towing or driving hard (when its boosting more)
its a 2002 15p with 108000 miles on it and has not overheated since i have owned it.
Are these known for cracked heads or should this hopefully be a simple head gasket replacement?
I just wondered if anyone else has had the same symptoms and could tell me what the remedy was?
Best regards,
Paul.

Paul Grant said:

Hi all, My discovery has been behaving itself since i purchased it, that is until the other day when i was towing my Ifor with a range rover on it! i noticed the next day i had pressure in the cooling system and the coolant level had gone down about 5mm. Anyway i suspected the head gasket so ordered a sniffer kit and tested it, and after about 5 mins of idling the fluid changed colour indicating combustion gasses in the cooling system.
It doesn't pressurise under normal driving but does when towing or driving hard (when its boosting more)
its a 2002 15p with 108000 miles on it and has not overheated since i have owned it.
Are these known for cracked heads or should this hopefully be a simple head gasket replacement?
I just wondered if anyone else has had the same symptoms and could tell me what the remedy was?
Best regards,
Paul.

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Hi paul, it could be either. They are known for warped or cracked heads (mine was cracked on a 10p) so best thing is to get the head tested. They can be repaired/reconned.

Bobdog said:

Hi paul, it could be either. They are known for warped or cracked heads (mine was cracked on a 10p) so best thing is to get the head tested. They can be repaired/reconned.

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Thank you for the quick reply, I have just ordered an Elring gasket set and a new set of bolts, ill pull it apart at the weekend and have a look.

Paul Grant said:

...its a 2002 15p with 108000 miles on it and has not overheated since i have owned it.

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Hi, as long as you dont have an additional coolant temp display to see the actual temperature the fact that the original gauge didnt leave the middle does not give you the certainty that the HG or head can't be hurt in time as you can drive it day by day for years at 110*C(or even 119 if the electric fan is not in working order) without even knowing it and that's not ''healthy" for the engine cos the gauge goes up only at 120*C if you see what i mean

Paul Grant said:

Hi all, My discovery has been behaving itself since i purchased it, that is until the other day when i was towing my Ifor with a range rover on it! i noticed the next day i had pressure in the cooling system and the coolant level had gone down about 5mm. Anyway i suspected the head gasket so ordered a sniffer kit and tested it, and after about 5 mins of idling the fluid changed colour indicating combustion gasses in the cooling system.
It doesn't pressurise under normal driving but does when towing or driving hard (when its boosting more)
its a 2002 15p with 108000 miles on it and has not overheated since i have owned it.
Are these known for cracked heads or should this hopefully be a simple head gasket replacement?
I just wondered if anyone else has had the same symptoms and could tell me what the remedy was?
Best regards,
Paul.

Click to expand...

very good diagnosing on your behalf
good call doing a sniff test best to find the issue sooner rather than later
to test the sensitivity of the sniff test use you own breath ... I normally do this as the fluid has a shelf life

there should be zero traces of combustion gasses in the cooling system regardless of driving style

you may find this will be a warpage issue or head lift under higher boost eventually this will get worse over time .....but don't hold me on this ..alloy heads can crack in many ways .....and the crack can open up when under load due to more heat involved (heat related issue )

if you do get the head pressure checked and there is a crack ..they may be able to fix it but this is only a bandade fix
if the head is lifting no doubt the cylinder head is now warped so its going to need skimming

the loss of the 5mm of coolant may of got to the point that it has escaped out of the over flow ...you may find it will find its own coolant level
to find out where coolant is going add a coke bottle to the over flow and get her working hard

I can confirm with my td5 that the ecu has a murhpy gauge Swichgage system printed into the ecu
I never bleed my coolant system correctly after a flush ..i then went for a drive i had an air lock ...the engine lost power limp mode then eventually shut down..... i needed to wait until the needle on the dash was not in the red to restart engine
this is how i learned not to depend on the cooling gauge