Leak on oil cooler advise please

[meowdmucker]

After getting my engine back from a rebuild I have an oil leak which appears to be coming out of the two upper bolts which attatch the oil cooler to its mounting.( twin port) The cooler is a new one. The main cooler mounting to case is dry but oil is running down the back of the cooler and dripping onto the cylinders through the gap in the cylinder cover tinware. It could be that they were never tightened enough by the builder as I could tighten them a couple of turns but not sure if they should have sealant behind them and if this extra couple of turns will seal the leak. ie should they be as tight as possible? It looks like there are small plastic washers with a metal spring washer above this. I don't want to fit the engine again and slill have the leak so would be grateful if anybody knows the correct way to secure the cooler to its mounting? Ps the engine builder was less than helpful with this matter- enough said!

 

[BJ1]

Since nobody else has replied I thought I might be able to help.

Try this ancient but good website http://www.oceanstreetvideo.com/vwtech/OilCoolerSealFaq.html Great vintage footage of oil seals.

I can't quite understand what your builder has done but on a tp oil seal there should not be any washers between the cooler and the stand. The nuts should be around 5 ft lb torque.

 

[meowdmucker]

Thanks Bj1 but I have probably misled you. It wasn't leaking where the cooler joins the case but from the two upper M6 nuts/washers on the outside of the cooler. Although not atttached where mine are the washers/nuts I mean are similar to those on page 25 of the Bently service manual ( nos. 21, 22 and 23). It's a strange place to find a leak which is why i'm hoping that the extra 2 turns of the nuts is all it needed to stop the leak. Have ordered some permatex sealant from Stateside and was going to coat the nuts/washers/threads with this before re fitting the engine. Just wondered if anybody else has had a leak here and what they did to stop it. Thanks again.

 

[Bookwus]

Hiya meow,

Are you sure that you used the correct gasket/washer/little rubber doughnuts for your particular application?

 

[meowdmucker]

Hi Bookwus,

The cooler was installed by my engine builder so it is possible. I'll see if you can buy the washers/ etc seperately and replace them if you can.

Cheers

 

[Bookwus]

Hiya meow,

The reason I asked.................

If one is putting an offset oil cooler on a case originally intended for a twin port the installation should be pretty straightforward. However, it is common to upgrade the cooling system from a single port fanshroud to a twin port fanshroud. Doing so requires mating up an offset oil cooler to a single port case. Since the oil passages on almost all single port cases were 8 mm and the oil passages in an offset oil cooler are 10 mm, one has a problem with seals (the little rubber doughnuts) at that point. There are special seals made for this transition. Using the wrong seals at this point could/will cause leaks.

Also, there is the matter of torque. These seals want to be firmly seated in their spaces. However, over tightening them is not a good idea. This is one of those spots in engine building in which one wants to pay VERY close attention to torque specs and proper procedure.

 

[Bookwus]

Hiya meow,

The reason I asked.................

If one is putting an offset oil cooler on a case originally intended for a twin port the installation should be pretty straightforward. However, it is common to upgrade the cooling system from a single port fanshroud to a twin port fanshroud. Doing so requires mating up an offset oil cooler to a single port case. Since the oil passages on almost all single port cases were 8 mm and the oil passages in an offset oil cooler are 10 mm, one has a problem with seals (the little rubber doughnuts) at that point. There are special seals made for this transition. Using the wrong seals at this point could/will cause leaks.

Also, there is the matter of torque. These seals want to be firmly seated in their spaces. However, over tightening them is not a good idea. This is one of those spots in engine building in which one wants to pay VERY close attention to torque specs and proper procedure.

 

[meowdmucker]

Thanks bookrus,

I'm going to take it apart, buy new seals and have a go myself, I can't do any worse surely. Thanks for your help and advise.