1998 V70 XC Leaking engine oil cooler seals

[scot850]

I ask the question a few days ago, but got no answers. So trying a different way. How does the oil cooler thermostat work (I know how a normal thermostat works)? I'm assuming it stays closed until the oil temp. gets to certain level and then the thermostat opens and allows the oil to circulate through the cooler.

Having replaced the cooler lines a couple of months ago, and the radiator about a year ago (all Volvo OE parts) it looks like oil is leaking from the seal between the new lines and the radiator connection. I would expect the line to be reasonably tight in the connection, but they turn easily, so presumably they are leaking around the 'O' rings for some reason. I am always careful fitting 'O' rings and use clean engine oil to lube prior to fitting. There is always a change I could have nicked the ring, but assuming I didn't why would they leak? If the thermostat is faulty would this cause enough pressure to cause a leak? If the thermostat is stuck shut, is that a problem, would it not just by-pass the oil cooler as when the oil is cold, and just mean the engine oil will run hotter?

As the thermostat is now NA at Volvo, is there an alternate other than used?

Thanks,

Neil.

[rspi]

Those are great questions that will likely go unanswered about the oil cooler. Usually when they go bad, they howl.

As for the leak, I would replace the seals. If that does not stop the leak, get fatter seals.

[erikv11]

I would also expect the line to be reasonably tight. First thing I would try is zip ties around the little clamps on the cooler lines at the rad. Are you sure the clips are put on in the proper orientation? There is a front and back.

The best alternative to the cumbersome oil cooler lines and thermostat is to swap in a newer oil pan, where the oil cooler is mounted directly on the pan. 'Some '99 and all 00 x70s then all models up to 04 or something.

[scot850]

Thanks Eric. I'll add this to the list, as again, I know there is a right way around for the clip (new clips were supplied with the hoses), but again worth checking anyway. By loose though, I should say, you can easily rotate them, but didn't notice any back and forward movement. But I'll check anyway.

I would consider the oil pan if there were no other options, but not my car now and not my money to spend. Had the pan removed and re-sealed last year with new 'O' rings in the pan. But as the thermostat is no longer available new I guess an old one or replacing the pan with the new style would be the only options.

Neil.

[Ozark Lee]

The sockets need to be almost surgically clean when you install the lines or the O rings will get damaged.

I've never heard of any problem with the thermostat that hurts anything, they just get noisy on startup.

...Lee

[cn90]

- I'd get a new O-ring from dealer.
- Metal Clip: THICK side toward radiator. Then use a screw-type clamp to tighten it.
Old clip has a tendency to be loose.

All detail in the thread I wrote below (ATF Cooler Line Rebuild):

https://www.matthewsvolvosite.com/forums ... hp?t=55794