Hi All, I've got a passat of 115 that I got with a blown oil cooler. Hoping it was just the cooler, I replaced , with a used one (I got off a running car with nice pink coolant), it ran up perfect and I flushed it thoroughly running it up to temp, with no other symptoms. I then took it up the lane and after giving it a bit of oompf up the hill, when I came back it had popped the oil cooler again, with the oil going into the coolant again. Someone suggested that if it was overdue an oil change, or had slightly the wrong oil in it, there is a pressure reg on the oil pump that might have got stuck open, not regulating the oil pressure. I don't know if the pd oil pumps work this way. Nor can I find any reference online, in the Haynes etc to what the right oil pressure should be. Im pretty confident that it's not headgasket related especially as it showed no excessive pressure in the coolant, and the oil has gone into the coolant, not the other way around. Open to being wrong though. I want to test the oil pressure theory, just need to know what it should be, then I can determine whether it needs a pump and then a new oil cooler. If anyone knows what pressure it should be making, or has any other suggestions as to what the cause might be, Id really appreciate some info. Cheers
It was coming up due a service when the first oil cooler popped, (before I got the car), so when I replaced the cooler the plan was to make sure everything was ok and then service it, but since it popped again straight away, I wanted to identify the cause, then get everything sorted.
I wonder if there's a blockage creating excessive pressure? If it was mine I'd check the oil return from the turbo to the sump is free flowing - people do all sorts of bodging to sell a car on with faults
It's interesting you mention a blockage and the turbo oil return, as on the last run when it popped again, it was smoking a bit, where it hadn't been before. Maybe I should bypass the cooler, flush the coolant, do a flush on the oil and see what it's doing. A mate checked autodata for me today, and it should be making 103psi @ 2k rpm. So I have a reference now.
From ElsaWIN, Dox could be on to something: At 2000 rpm and an oil temperature of 80 C the oil pressure should be at least 2.0 bar. At higher engine speed, oil pressure must not exceed 7.0 bar. Renew oil filter bracket, if necessary and from the oil pump diagram: Oil pump: - With 12 bar pressure relief valve. - Before installing, check that both dowel sleeves for centring oil pump on cylinder block are fitted. - Renew if running surfaces and gears are scored.
So have had limited time to do much more on this, but I did get time to put an oil pressure gauge on it and test what its actually making. I didn`t have the vagcom with me so I didn`t check the oil temp but it had been running for a bit and had a little spin up the lane. It made 70psi @ 2k and 90psi and a bit @ just over 3k. So it doesn`t seem wildly high. Still lots of smoke under load. Had a look at the filter housing, which I took off the spares car at the same time I got the replacement oil cooler, and there is a very basic, spring loaded one way pressure reg set up inline to the filter itself.
Unfortunately not at the moment, the oil press. gauge I have is electric and the bulky sender fouls a water pipe, which I have to disconnect, only allowing me to run it for a few moments.
