Astra J 1.7 Diesel EcoFlex major coolant loss

[andyiley]

I am still leaning away from chg/head issues for the same reasons as stated before.

Sniff test pass, pressure test pass, no oil in water/water in oil. (Before anyone says anything, yes I do know these are rules of thumb & there are exceptions)

EGR I have no real experience of, so can't comment.

I am still leaning towards water pump not operating correctly. As said before I have come across the exact symptoms before (sniff pass, pressure test pass, no oil in water/water in oil, heaters working, temperature up on slow/short trip, fine on long/faster trip) Which turned out to be the pump impellor blades rusting away.

I am not familiar with your particular engine layout, is there any way you could rig up a temporary inlet & hose to the pump from a large pop bottle or something, to see how well the pump actually pulls in the water? Or better still on the return from the engine to see the throughput?

[crossy67]

andyiley said:

As can be seen in the video, there isn't any.

No but the video wasn't taken when the engine is working hard accelerating at 60mph. The difference in compression between tick over and acceleration will be immense.

Good call on the EGR, just bypass it, it's only water cooled to cool the little bit of charge that gets back into the engine, won't hurt much with it bypassed.

[Pumaracing]

bearman68 said:

Having read the previous many posts, could I suggest it might possibly be, maybe be a faulty EGR valve.

If it were the EGR valve cooler I doubt if the pressure from exhaust gases would cause the expansion tank vent to blow-off. However I'm not familiar with the layout of that component on this particular engine. As this vent has been dripping with two different expansion tanks without the coolant temperature getting hot enough to boil then combustion chamber pressure seems to be the only logical cause.

[Pumaracing]

To the OP, there's a nice simple test you can do to throw more light on this. With the engine cold make sure the cooling system is full and just let the engine warm up at idle while you watch the expansion tank vent. This is an unthrottled diesel so there'll be plenty of combustion chamber pressure at all times.

If the vent starts blowing off and the coolant is definitely not boiling then you know it's combustion chamber pressure. You might want to turn the engine off from time to time so you can listen to the vent as well.

[andyiley]

crossy67 said:

andyiley said:

As can be seen in the video, there isn't any.

No but the video wasn't taken when the engine is working hard accelerating at 60mph.

I meant there isn't any anti-freeze!

[crossy67]

The difference between tick over and accelerating under full boost will be immense as said before. No load compression would be little more than cranking.

Take it for a hard drive then do a sniff test.

[bearman68]

Pumaracing said:

bearman68 said:

Having read the previous many posts, could I suggest it might possibly be, maybe be a faulty EGR valve.

If it were the EGR valve cooler I doubt if the pressure from exhaust gases would cause the expansion tank vent to blow-off. However I'm not familiar with the layout of that component on this particular engine. As this vent has been dripping with two different expansion tanks without the coolant temperature getting hot enough to boil then combustion chamber pressure seems to be the only logical cause.

Mmmm you might well be right. Having said that, EGR pressure must be up somewhere about 3 bar I would think, plus there is a direct heating effect from the hot gas into the water.
I'm not saying it is the EGR, only that it is possible, and relatively easy to check. Head off, or EGR blank. No contest for me.
My personal little action plan would be
1) Temporary EGR removal. Check with long hard run, and sniff test. If fail then
2) Strip out the water pump for a good look.
3) Steel seal / leak blocker / chemical warfare.
4) Head off.

Bugger of a job to remove the head.

[chriscross123]

Pumaracing said:

To the OP, there's a nice simple test you can do to throw more light on this. With the engine cold make sure the cooling system is full and just let the engine warm up at idle while you watch the expansion tank vent. This is an unthrottled diesel so there'll be plenty of combustion chamber pressure at all times.

If the vent starts blowing off and the coolant is definitely not boiling then you know it's combustion chamber pressure. You might want to turn the engine off from time to time so you can listen to the vent as well.

Hi, thanks for the suggestion - I ran the engine up idling from cold on Sunday. I shut down after 30 minutes and there was no evidence of leakage from the vent? I will check again but won't get the chance until the weekend.

Cheers

Chris

[chriscross123]

bearman68 said:

Mmmm you might well be right. Having said that, EGR pressure must be up somewhere about 3 bar I would think, plus there is a direct heating effect from the hot gas into the water.
I'm not saying it is the EGR, only that it is possible, and relatively easy to check. Head off, or EGR blank. No contest for me.
My personal little action plan would be
1) Temporary EGR removal. Check with long hard run, and sniff test. If fail then
2) Strip out the water pump for a good look.
3) Steel seal / leak blocker / chemical warfare.
4) Head off.

Bugger of a job to remove the head.

Thanks for the suggestions - I have ordered hose clip pliers so will try bypassing the EGR cooler by linking together the two cooler hoses and see what happens.

Cheers

Chris

[chriscross123]

andyiley said:

I am still leaning away from chg/head issues for the same reasons as stated before.

Sniff test pass, pressure test pass, no oil in water/water in oil. (Before anyone says anything, yes I do know these are rules of thumb & there are exceptions)

EGR I have no real experience of, so can't comment.

I am still leaning towards water pump not operating correctly. As said before I have come across the exact symptoms before (sniff pass, pressure test pass, no oil in water/water in oil, heaters working, temperature up on slow/short trip, fine on long/faster trip) Which turned out to be the pump impellor blades rusting away.

I am not familiar with your particular engine layout, is there any way you could rig up a temporary inlet & hose to the pump from a large pop bottle or something, to see how well the pump actually pulls in the water? Or better still on the return from the engine to see the throughput?

Thanks for your input. One comment - on the last visit to the dealers I was told it had now failed the sniff test - when I queried this saying they had told me it had passed before, they didn't have an answer. I've ordered a sniff test kit to check for myself.

I don't think there is a particularly easy way of accessing the pump pipework direct - probably closest option is one of the radiator hoses (I'm thinking get a length of hose and feed it back up to the header tank?). Its a bit of a pain because (as far as I can gather) the water pump has an electric clutch and it only pumps water when the engine is hot. Any thoughts on what sort of flow rate a 'good' water pump should give?

Unfortunately popping the water pump out is not straightforward - a special tool is required to take the tension of the (auxiliary drive belt.

Cheers

Chris

[andyiley]

Well if the sniff test has now failed then that is chg/head/egr.

If the pump has a clutch (didn't know that) then the only real way is going to be to get it out and test the clutch when you check the pump, as a weak clutch could also produce the same effect I described before.

Have you had a close look at the "special tool" required as many are quite simple to make up?

[chriscross123]

Well, my ebay sniff test kit turned up and I got home in time to test, and pretty conclusive that there are exhaust gases present. Not sure why the initial tests by the garage were clear (maybe the leak has got worse since then) but now seems very obvious.

I think what has been throwing me is the electric clutch on the main water pump. Basically the water pump seems to cut in and out in a similar manner to the fan. Running it up to temperature tonight the hoses were all different temperatures (as if there was a blockage), then I heard the water pump click in and start pumping, seconds later all the hoses had come up to similar temperatures.

The EGR valve is mounted on the EGR valve cooler, so I think the only way to rule out the EGR valve cooler is to bypass it as previously suggested.

Cheers

Chris

[mighty kitten]

On a similar note I've done two BMW with the fully electric water pump this month similar year and mileage but if you've got gases in the coolant is be inclined towards a cracked head . Egr leaks often let water into the inlet manifold as it cools down with some lumpy or poor starting especially the Volvo v40 diesels for some reason