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[edgi]

Hi All

Ive got a omega 2.5 v6 elite on a 98 plate, i bought it earlier this year and couple of months ago had to change the water pump as its bearings had worn, because of this it was pouring alot of water out from the water pump seal, had to keep topping expansion tank up as you would expect. pump and new seal installed, topped up with coolant, bled the system and after every journey it looses approx 1/2 a litre. changed the heater bypass valve but still happening.

no leaks from the coolant found anywhere, carpets inside dry, engine bone dry, no leaks on the floor, havent noticed any steam, oil colour is as it should be (no mayo on cap or dipstick) no oil in coolant tank.

Tried adding coolant leak dye and checked all over the engine and in side footwells, nothing showed with the uv light.

Changed the coolant tank for a replacement along with new cap but still no luck.

Temp gauge is fine, fan kicks in when its supposed to then drops out once cooled down a few degrees, as ive done a few journeys the coolant goes down but not completely empty the tank, gauge will rise to just the 100 mark before the fan kicks in. soon as i hit the throttle hard or keep to a long stretch of road without slowing down/stopping the gauge will sit just above 90.
Once i top the coolant up the gauge behaves as normal.

Slight condensation out of exhaust when revved but think that could just be down to the catalytic converter as had that on a vectra b.

Heater blows hot and cold as its supposed to.
If any one has come across this before or knows of a solution i would be greatful if you could share as im stumped lol

Cheers

[powerslinky]

Hi All

Ive got a omega 2.5 v6 elite on a 98 plate, i bought it earlier this year and couple of months ago had to change the water pump as its bearings had worn, because of this it was pouring alot of water out from the water pump seal, had to keep topping expansion tank up as you would expect. pump and new seal installed, topped up with coolant, bled the system and after every journey it looses approx 1/2 a litre. changed the heater bypass valve but still happening.

no leaks from the coolant found anywhere, carpets inside dry, engine bone dry, no leaks on the floor, havent noticed any steam, oil colour is as it should be (no mayo on cap or dipstick) no oil in coolant tank.

Tried adding coolant leak dye and checked all over the engine and in side footwells, nothing showed with the uv light.

Changed the coolant tank for a replacement along with new cap but still no luck.

Temp gauge is fine, fan kicks in when its supposed to then drops out once cooled down a few degrees, as ive done a few journeys the coolant goes down but not completely empty the tank, gauge will rise to just the 100 mark before the fan kicks in. soon as i hit the throttle hard or keep to a long stretch of road without slowing down/stopping the gauge will sit just above 90.
Once i top the coolant up the gauge behaves as normal.

Slight condensation out of exhaust when revved but think that could just be down to the catalytic converter as had that on a vectra b.

Heater blows hot and cold as its supposed to.
If any one has come across this before or knows of a solution i would be greatful if you could share as im stumped lol

Cheers

Are you still losing 1/2  a litre after every journey ?     Thats quite a big leak  IMO       I would have thought you could see where that was leaking  

 Another diagnosis is that around that year '98 (I  think it was)  2.5 s  were prone to head gasket failure on one of the rear pots I believe 

[amba]

Sure do,Al.

My old 1998 2.5 Elite lost coolant for the last year of my ownership.Like posted I replaced/resealed and checked everything eventually tracing it back to a leak at the back of the N/S head on the corner of #6 cylinder.You could see a crusty build up of evaporated coolant on the head and behind the bracket for the dispack.

Given the costs involved in replacing against car value I struggled on just topping up every few weeks and learnt to drive to reduce the problem.

Worth having a very close look at the back corner of the 2/4/6 bank head as thats the culprit area as think I have read the water seal on the h/g is at the corner and perishes so wont leak oil into water or reverse,just coolant to atmosphere.

[edgi]

Hi Big AL :Yes after every journey it looses approx half a litre, doesnt matter how long the journey is it looses the same amount, its as if it dumps half a litre somewhere from start up. No signs of leaks anywhere.
once it gets to almost empty of the coolant tank it wont loose anymore.

Hi Amba: The only leak around there is oil from the rocker cover seal (more like slight seaping than a leak really)
There was some crusty red coolant on the big hose that attaches to the n/s/f of the engine so replaced including clamp but must have been from some previous issue and not cleaned up.

Engine is pretty clean and tidy for its age, just cannot find the leak or signs of it.

cheers

[YZ250]

Sure do,Al.

My old 1998 2.5 Elite lost coolant for the last year of my ownership.Like posted I replaced/resealed and checked everything eventually tracing it back to a leak at the back of the N/S head on the corner of #6 cylinder.You could see a crusty build up of evaporated coolant on the head and behind the bracket for the dispack.

Given the costs involved in replacing against car value I struggled on just topping up every few weeks and learnt to drive to reduce the problem.

Worth having a very close look at the back corner of the 2/4/6 bank head as thats the culprit area as think I have read the water seal on the h/g is at the corner and perishes so wont leak oil into water or reverse,just coolant to atmosphere.

My old 98 elite was the same but, as amba said above, it only needed topping up every so often, not on a daily basis. Never once saw a drip because the engine heat evaporated it before I could see it. Only evidence was a thin white water mark on the rear corner of 246 bank as said above. I did eventually replace the head gasket on mine.

Hi Big AL :Yes after every journey it looses approx half a litre, doesnt matter how long the journey is it looses the same amount, its as if it dumps half a litre somewhere from start up. No signs of leaks anywhere.
once it gets to almost empty of the coolant tank it wont loose anymore.
............

As said, half a litre regardless of journey length is a significant leak. Are you saying that if you didn't top it up when the coolant level reached near the bottom of expansion tank it wouldn't lose any more?
Maybe time for a pressure test to eliminate the expansion tank. 

[Rods2]

It might be the oil cooler plate or the coolant bridge washers, both of which are hidden by the Plenum and intakes, which you will need to remove to check. Alternatively, it might be the head gasket leaking when the engine is cold or left to cool down and the coolant system depressurizes.

You can use your old cap by adding a tyre valve to it to make your own coolant pressure system. There is a guide in the maintenance section for doing that.

[edgi]

[\quote]
As said, half a litre regardless of journey length is a significant leak. Are you saying that if you didn't top it up when the coolant level reached near the bottom of expansion tank it wouldn't lose any more?
Maybe time for a pressure test to eliminate the expansion tank. 
[/quote]

Correct, Thats why i suspected the expansion tank and/or cap, if i dont top up it wont completely empty the tank, there would always be some although little left.

Thanks for all the replies guys, i'll pressure test it over the next couple of days and if that doesnt shed any lights gonna be a strip down job. (this is gonna be fun LOL)

[ffcgary1]

Remove the plenium and intake manifold and have a look at the oil cooler plate, it runs between the v of the engine and it is prone to leaking and it leaves a crusty white/pinky stain, it will also let you see the coolant bridge between the cylinder heads at the rear of the engine, this also leaks where the banjo bolts go through the bridge.
At the front of the v is the thermost housing and transfer pipe, this is also a common leak area but be warned that the housing and transfer pipe can be a bugger to seperate without damage to either part. IF all shows no signs of leaking then move onto the rear of the 2 4 6 head, and as you have removed the intake it will give you more scope to see any issues. use a mirror to see where your eyeballs wont get to.
good luck and post back any findings and pics if needed.
Gary.

[edgi]

Thanks Gary,
Will post back with what i find.
I dont mind the regular topping up, its the curiosity of where its going is bugging lol

[robson]

Have you checked the rad whilst engine running.I could not find a leak until I found a tiny leak on the bottom corner of the rad. As the rad is hot the water burns off and the leak is hard to find.

[edgi]

Have you checked the rad whilst engine running.I could not find a leak until I found a tiny leak on the bottom corner of the rad. As the rad is hot the water burns off and the leak is hard to find.

checked radiator during my many checks, nothing seen, done a few cold starts and run up to temp whilst checking for leaks and steam. switched off and continued checking to see if anything appeared while engine was cooling down, again nothing. plus nothing has shown with the leak dye using uv light. only thing left is a pressure test and major strip down as other members have suggested.

[edgi]

**UPDATE**

Finally managed to get some free time to properly look over the car and strip it down.
nothing out of the ordinary was found at first, but on closer inspection of the hose that runs from the coolant bridge to hbv there was a split in the pipe.

Just at the edge of the spring clamp was letting out water i imagine when the hose heats up and expands, with the tear being directly above the exhaust downpipe it was burning off straight away.

Fitted new pipe and so far all is ok.

But about 3 days before i stripped down the car the cabin heaters wont blow hot air, with engine at full temp i switch blowers on and hot air comes out but gradually over 60 seconds drops to cold, if car is stood still and i rev it then still remains blowing cold.
If im driving and open throttle pretty hard then hot air will come out until i drop revs.

Any ideas?

Cheers

[05omegav6]

That sounds like a thermostat issue... But leak could be heater matrix, which won't help the cabin temp either

[edgi]

Temp seams to read normal, 92 degrees constant driving, slowing down/standstill rises to about 98 and fan kicks in.

i know usually thermostat issues will either be one of 2 things, constantly overheat or run too cold. gonna try and get round to flushing matrix out this weekend and if not sorted then possibly inspect/change stat.

hopefully its not head gasket related