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[MartinV6]

Hello guys, and greetings from Bulgaria!

Your community has helped me a whole lot these past three months with getting to know my Omega 2.5 24V, lovely car, but it had some issues... we sorted most of them, but now there is another problem.
A few days ago I played with the throttle pedal for a few slide corners, nothing unusual... after driving with regular pace for a few miles, I pulled over for a 4-5 mins... the heating was fine, I always have my eyes on the gauge... after starting the car, I noticed that the needle was above 100 degrees, where it had never reached before (but not on the red zone) and the little red light flashed, but immediately after starting the engine it dropped hard on little below 95 degrees, which it runs most of the time on.... I drove home, everything was fine.... the next day I started the car, and it started heating up a little faster than usual, after a few mins it hit 95degrees and then dropped hard at 90.... the heating inside was not the same, however it was blowing warm... and when I give it revs, it heated more... so  I figured - it lost coolant, which it did - the expansion tank was almost empty... so I figured next  - it must have a leak somewhere - and there it was - leaking somewhere around the middle of the car, in the point where the engine joins the tranny... but it was leaking from somewhere above... next strange thing - while still being hot, a slowly unscrewed the cap of the coolant tank and when it bubbled, the antifreez was ok to touch!  slightly warm, but not boiling hot! .... after further investigation, we concluded two things - the car only leaks when the engine is running (it leaks quite a lot, not only dripping - for a 10min idle it almost lost the whole expansion tank content again) and the other - the back of the engine is dry, the leak seems to be from the right side of the engine ( for you it's the drivers side, for me in Bulgaria is the passenger - we are LHD) - the starter is wet, and seems to be leaking from above/around it..      ...we recently serviced the car - the whole timing kit including water pump; the HBV valve, the coil pack... (we checked that valve first for leaks...)   so, any suggestions as to where the leak may be from?

Thanks in advance!     Your community is awesome!

[Bojan]

Hi!

Check the hoses around the HBV - you say that it was removed and changed, there is a good posibility that some clip (especially if it is a jubilee-clip) has either got loose, or it bit trough hose.

[MartinV6]

that was the first check we made - everything is dry... the back of the engine is dry, so I exclude the HBV valve and related hoses, as well as the oil cooler -if it was the cooler, it would leak out the back I guess....

when the car heats up and is idling, you look underneath and see a steady thin "waterfall" leak of coolant going down... not only a few drips a minute for example... could it be thermostat? I don't know where it is, but as I said, the starter of the car is wet, so presumably it is leaking from somewhere above/around it...

[powerslinky]

Possible coolant bridge leak.   Plenum & inlet manifold off to see this I think .

Have a look at "coolant sensor replacement" in the  maintenance guide  V6 engine section. This shows some clear pictures of what you need to see . The actual alloy coolant bridge & the 2 small coolant pipes connecting to it. The coolant bridge is at the rear of the engine in the "V" valley  & can be worked on once plenum & injectors etc.are removed.

[powerslinky]

Possible coolant bridge leak.   Plenum & inlet manifold off to see this I think .

Have a look at "coolant sensor replacement" in the  maintenance guide  V6 engine section. This shows some clear pictures of what you need to see . The actual alloy coolant bridge & the 2 small coolant pipes connecting to it. The coolant bridge is at the rear of the engine in the "V" valley  & can be worked on once plenum & injectors etc.are removed.

EDIT:Had another read through your post . . . back of engine is dry you say  . . .so unlikely to be what I suggested

Thermostat is opposite end of  the valley , directly behind the cam belt cover assembly. There is a V6 thermostat change guide in the maintenance guide section . This will show you its position 

[Doctor Gollum]

Could be headgasket in order to get to the starter

[MartinV6]

I thought about the headgasket, and I am hoping it is not it....     because it has to be blown pretty badly in order to leak so much... and the car did not overheat.....it tooke me two months to settle the car and I enjoyed only a few days of worry-free driving...
 
thanks for the replies, guys, hoping today I can have the chance to look again on a car lift...

[Bojan]

I tought about the headgasket, and by the 'looks' of it, it just might be  . But first, check the back one more time, in detail. It's very cramped there, and you might overlook a leak.

[MartinV6]

Tomorrow we intend to get the car on a lift and even remove the starter for a better view above it. if it is the gasket, I do not have the money to fix it, so hopefully it is not that.... but it leaks a lot, so.... fingers crossed, guys!  will post after we check.

[MartinV6]

guys, I'm puzzled 

today we got a big jug of antifreeze, tools and got the car on a lift....

initially the leak occured, we removed the heatshiled of the right manifold for better view, no need to pull the starter out for that... and still could not determine the leak source.... but after some fiddling we found out that the coolant was not circulating OK (I have oil cooler failure and there is oil in it....)   - the two top hoses coming out of the coolant tank were clogged... we managed to unclog them and the car held a correct temp at the gauge... but the pressure was lower now - you could squeeze the big hose coming out on top of the radiator....  we started the engine and waited to cool several times, and we topped more than 2 liters antifreeze total - tha car had lost that from somewhere (supposedly where the visible leak was)...  and we concluded that the car was with faulty cooling circulation and for some reason it made an over pressure in the system and leaked antifreeze and got a little above the 100 degrees the other night, when my "story" started... we got the car back on the lift while running and - no leak!!! even the wet space above the exhaust manifold was evaporated!!!     like a magically self restored head gasket, if it was the head gasket in the first place, that is....    now the car was running and no leak noticed.... next we will remove the ram, bypass the oil cooler to not let oil in the coolant system, flush the system several times and then we will see if the leak reappears... a few days ago the leak was visible, as if you let the water from the sink running thin - that much! and that was after 7-8 minutes at idle..

so now we think it overpressured because of the clogging in the coolant system and lost antifreeze from somewhere and thats why I saw the temp gauge go past the 100 mark..... remaining question is when we clean the coolant system and run the car, will the leak reappear......

[Andy H]

I know that you have already changed the HBV but the symptoms still point to the HBV being at fault

[Bojan]

Well, it's great that it's not a headgasket.
You say that hoses that are connected to the expansion thank were clogged - with mayo I suppose?
If so, it's very possible that the leak was coming from the connection point, where the hose that goes to connection tank is connected to metal coolant return pipe (one that goes from the back of the engine, next to the RH exhaust manifold, to the radiator) - if no place to expand, it must either leak, or burst a pipe.

BTW, if you are driving with coolant-oil mixure, your cooland hoses will deterorate, and start bursting in future.

[MartinV6]

that is why I intend to not drive the car until I bypass the oil cooler and flush through the system until it is clean... the head gasket is not out of the equation yet - we're just not sure because one day the leak is visible and the other day it is completely gone..... my main reason to think it is not the gasket is the fact that the car did not reach the critical temperature, and it stood above 100 degrees very little time...  today we will try to find time and see if we can get the plenum out and bypass the oil cooler, then start flushing.
oh, forgot to mention - the back of the engine is completely dry, so it is unlikely to be the hbv valve leaking or faulty - there is heat inside the cabin and it got better when we unclogged the hoses to the coolant tank, especially the one coming from the radiator was sealed shut.

will post as soon as we find something

[Bojan]

How are you planing to sort out the oil cooler?
My advice - replace it with new unit. Get a new cover plate, too.
Or, if getting one is too expensive, or too difficult, you might place external air cooled.

But don't choose to drive (long-term) without an oil cooler of some sort.

[MartinV6]

now we want to bypass it to make sure the coolant system is all ok with pressure and it is clean to see how the car is performing and if there are leaks... if all is good, I plan mounting an external kit, I found a tutorial about it and I think it will be a good and cheaper soluiton.... otherwise I might have to put better oil and change more frequently, 6-7 000kms ,I guess...