Back pressure from engine

andyeire

Just thought somebody on here could give me some ideas.I had the cylinder head gasket replaced on my Toyota Estima .This solved overheating problems the water pump and radiator were also replaced .Now ihave back pressure from engine forceing water from expansion tank.The car is not overheating just needs water twice a week .I had it looked at and am told that it could be a crack somwhere else on the engine block.A new engine will be the guts of 2k fitted am i getting b/s or this sound right.I have checked prices of the engine in the UK so i know the price isnt that far of .Is there any other solutions .I am thinking of sticking some 'seal up' in the engine i cant do any more damage ,or can i...... the engine is a 2.2 turbo diesel. thanks

Saturnine

This might sound stupid but have you checked if the thermostat is stuck closed?If the engine was cracked it would leak all the time.Can you see traces of oil in the expansion tank?

AMurphy

Why are we sure the new head gasket is not once agian the problem?. It is possible a very small scratch could be leaking across the gasket face.

Interceptor

Andy, when the gasket was changed was the thermostat checked? Its a pig to get at and you will lose all your coolant when you take it out, but it should open when dropped in a mug of boiling water and is easy to check. Most car systems run pressurised to raise the boiling point of the coolant and prevent localised boiling in the system but if the expansion tank cap or its rubber seal is cracked, you will lose pressure and the system will empty itself. Leave it running at operating temp and see if you can see where the coolant is leaking from. You shouldn't use ordinary water in your engine - its ok to get you home but long term you should use proper coolant or antifreeze/water mix.

If the problem is as you describe, and the rad was changed, don't put any temporary 'seal-up' radfix/barrleak type additives in until you know where it is leaking from. Maybe it is as simple as a loose jubilee clip on a water line from the replaced rad?

If the head gasket is gone again it might be difficult to start, lumpy on tickover or there will be white/creamy goo in the oil or oil in the expansion tank. With high compression engines (diesel) you can sometimes smell fumes in the expansion tank or see bubbles coming up in it.

'c

lomb

defective water pump?new one could have a leak. u need to add a ultraviolet dye to the coolant and don fancy glasses to see it/use a uv light. prop need a pro to do this unless u can afford the equipment.

http://www.diynetwork.com/diy/en_maintenance/article/0,2021,DIY_13808_2274387,00.html

http://www.autobarn.net/trst.html

BrianD3

Lads he said the coolant is being expelled through the expansion tank cap. So he already knows where the "leak" is.

As AMurphy says, the new HG could have a minor blow or have been fitted poorly. I think it's unlikely that a brand new water pump and radiator would be causing the problem though. I'd also assume that the thermostat and expansion tank cap are OK because the mechanic should have checked to see if they were the cause of the overheating before he went and changed the head gasket. Assumptions can be dangerous however

A quick way of checking the thermostat yourself - check that the radiator and hoses leading to the rad get nice and hot when the car has been running a while. If they do then the thermostat is probably opening OK.

And yes, it is entirely possible that there could be a crack in the engine block which is allowing exhaust gases into the coolant. This will cause similar symptoms to a blown head gasket and could explain why there are still problems even after fitting a new gasket.

Another possibility - I wonder could a bad airlock in the system cause the problems described. Air will have been introduced into the system after changing the gasket and if the system wasn't bled properly after refilling there will be problems.

Just throwing out a few ideas

andyeire

Mnay thanks for the replys .The problem could be the head gasket again it has the same symptoms .I am using a different garage than the one that replaced the gasket,it costs about 900 euro to replace gasket.The engine is below front seats and is a pig to get to .The previous garage seems to have removed the thermostat and drilled holes in it to hide the problem when i brought it back to them.They never told me this they just said it had got stuck.This is the reason i went to a different garage to get a secound opionon.If i could guarentee that it is the head gasket again i could get that done but is there any way of finding out where the crack is.My biggest fear is to get the work done again and still not fix the problem.The engine is running great not overheating not gunge on oil filler cap no oil in expansion tank .It handles motorway speeds no problem.

BrianD3

My advice is, bring it to the "competent" garage, get them to bleed the cooling system and fit a brand new cap to the expansion tank and see if that solves the problem. If it doesn't, get them to investiagte the head gasket using pressure tests, compression checks, exhaust gas tests etc.

lomb

might want to consider flogging it at auction to cut your losses. although id try the ultraviolet solution personally.