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[Darth Loo-knee]

Water in Oil?  Steam out of exhaust??? is there any more symptoms??


Looking at buying a v6 which is apparently pressurizing the cooling system, is this a sign of head gasket failure? if not what could it be??? could i drive it home about 20 miles??



Cheers Guys

[Dazzler]

Sounds very much like a head gasket failure I would not advise driving it very far due to the fact of water in the oil, so the engine will not be getting lubricated, thus you could end up with a scape engine

[Kevin Wood]

Pressurising the cooling system - could be. However, if it's leaking coolant sometimes this is mistakenly blamed on the HG whereas it's actually just overheating due to lack of coolant opr another issue and then blowing the cap. Could well be a HBV failure, dodgy water pump, thermostat, blocked rad, etc.... If it's the only symptom, I'd say it's unlikely HGF.

Steam out of exhaust - you will get moisture out of the exhaust anyway, especially if the exhaust system's cold. If the engine is losing significant amounts of coolant into a cylinder you'll get more. If there's plumes of it there's a problem, otherwise difficult to be conclusive.

Water in oil is unlikely and points more to oil cooler falure on a V6.

Oil (or sludgey cr@p) in the coolant is a symptom of both HGF and oil cooler failure.

Conclusive checks for HGF are to put an emissions tester in the expansion tank and check for fumes, and to do a compression test.


Kevin

[Kevin Wood]

Sorry - regarding driving it home. Take a look at the state of the oil (including under filler cap) and coolant and make a decision.

If it's reasonably continent and isn't dropping its coolant immediately and the oil is looking like it will lubricate to some extent, and hasn't gone over the MAX mark due to being diluted with water I'd say it won't do any more harm but take spare fluids and take it gentle.

Kevin

[Marks DTM Calib]

Think you got that the wrong way round....

Oil in coolant is cooler failure and very VERY unlikely to be headgasket (think about  the oil and coolant pressures through the head gasket)

Coolant in oil is also a symptom of oil cooler failure to.....but, might be head gasket.

Just remember that due to a lack of understanding of basic engine theory, head gasket is all to commonly miss diagnosied and replaced.....

[Kevin Wood]

Yep, sorry, brain - keyboard interface issue ;-)

Kevin

[Darth Loo-knee]

So if i took loads of water and kept topping up would i get 20 miles home, or I wonder if the RAC would bring me home??

[Matchless]

The coolant should be pressurised, the question is wether the pressure is so high that it causes the pressure relief valve in the coolant filler cap to lift.
If the oil cooler has gone then there will be lots of oily mayo in the header tank, the radiator will be blocked so the engine will overheat and the coolant pressure will be high as a result.
If it is a head gasket failure then there will be obvious over-pressurisation and mild overheating but minimal signs of oil in the coolant. The combustion gasses escaping from the cylinder to the water jacket causes the pressurisation and water is lost as the pressure relief cap lifts.

As to driving....you have to make a judgement. If the dipstick looks like the oil might be floating on water do not start it.....the oil pump will pick up the water and circulate it around the bearings. If you do decide to drive it then go easy and keep an eye on the temperature....do not let it boil. If the temp gauge is high then falls you must stop and check the water level as this is a sign that the coolant temp sensor is no longer submerged in water...ie you are about to kill an engine.

If it not too far I would get a tow pole from Machine Mart and tow it.......less issues with tax and insurance this way and if the engine is able to idle it would provide power steering and servo brakes without too much risk of overheating.

[Kevin Wood]

So if i took loads of water and kept topping up would i get 20 miles home, or I wonder if the RAC would bring me home??

He He. Drive it 20 yards up the road and "break down".

"Hello, RAC? I think I may have bought a Lemon"

 

It really depends how fast it's losing water. If it starts and warms up without losing huge amounts of water it'll probably be good enough to get you home, with a few stops to check.

May be worth loosening the expansion tank cap if it does appear to have a coolant leak, as this will reduce the system pressure. However, this will also cause it to boil over if you hammer it or get held up in traffic so it will need an eye kept on it.

Kevin