Fixing Intercooler Cracks

[Ray!]

Recently, I started to hear odd whistling noises under the bonnet when the engine was relatively cold and under high boost, and also when warm and under high boost. After a bit of investigation, I discovered that my intecooler was affected by cracks where the cooler pipes attach to the header tank. This is not uncommon and mine has probably been exacerbated by my intercooler fan attachment. This is probably due to not being entirely careful as to how I tensioned the bolts attaching the fan to the intercooler, causing stress, as evidenced by the fact that the cracks have occurred at opposite corners of the intercooler.

Here's a shot of one crack, just visible where you see the darker mark:

Anyhow, I wasn't in a position to get a new intercooler at the moment, so I sought ways to fix the problem as best I could. As it turns out, I had a tube of Loctite Metal Magic 98853, which had never been used and after some internet searching, found out that it might just do the trick. So after letting the intercooler cool down fully, I removed it and found the offending cracks, one on top (as in the photo) and two underneath, which required removal of the fan assembly. The Metal Magic is a two part epoxy resin that comes in a roll inside a plastic tube, all you do is tear off a small piece and start kneading it vigrously for a few minutes until is turns dark grey. You need to use rubber gloves for this, as the stuff will stick to your hands like the proverbial and is near impossible to wash off. Once ready to use, you have about 3 mins to work it into place before it sets and after about 10 mins, it's almost rock hard.

Before I filled the crack with the Metal Magic, I cleaned the area with liberal use of contact spray to get rid of any oil and muck, and then followed up with MAF cleaner to remove any residue left by the contact cleaner. By rolling the Metal Magic into a very thin roll, I used a tooth pick to push the epoxy into and around the cracks and once finished, left the intercooler overnight before starting the Patrol the next day. This is what one of the repairs looked like:

After about three or so weeks of driving around, the fix has certainly worked. I can still sometimes hear just a slight whistle when cold, but that could be a crack that I've missed. But as the whistle is so minor, I will probably live with it unless it gets worse and by that time I might look at a replacement intercooler.

If there was a more 'liquidy' sealant about that had similar properties to the Metal Magic, then it would have been very easy to fix these minor cracks. That said, I would heartily recommend carrying a tube of Metal Magic if going out bush etc, as this stuff is able to reapir many things that may break or leak when out and about.

Cheers

Ray

[Dye-04]

Good write up Ray. At fraser Island my mate broke an engine mount, the engine fan went through the radiator. We repaired it with Loctite Metal Magic. He drove around like that for weeks. It saved his arse big time!!!

Edited May 19, 2012 by Dye-04

[TheFlyingBadger]

given this problem, would you recommend just hanging the intercooler fan by the bottom flanges only rather than drilling through both?

[Ray!]

given this problem, would you recommend just hanging the intercooler fan by the bottom flanges only rather than drilling through both?

I went through both flanges so that it balanced the weight top and bottom, but clearly I didn't tension everything evenly and created stress. At least that's my guess, but these pressed type intercoolers are prone to having problems anyway, so it may only have been a matter of time regardless.

Cheers

Ray

[Nutta]

How do you think sikaflex would hold out on that if it was prepared properly? And put it on fairly thick at the leak too i mean.

[Ray!]

How do you think sikaflex would hold out on that if it was prepared properly? And put it on fairly thick at the leak too i mean.

Depending on the type of Sikaflex, it could work quite well. It just needs to be a material that is able to stand the pressure. I guess it's a balancing act between rigidity and flexibility. The Loctite is very rigid, so won't expand and contract with the alloy (I think), but holds on like the proverbial. Sikaflex will expand and contract, but can it stand up to the pressure that's exerted? I'm sure that there would be a product available that would do both and be within the requirements for this sort of job, it's just a matter of finding it..

Cheers

Ray

[Bogmeister]

I went through both flanges so that it balanced the weight top and bottom, but clearly I didn't tension everything evenly and created stress. At least that's my guess, but these pressed type intercoolers are prone to having problems anyway, so it may only have been a matter of time regardless.

Cheers

Ray

My Ex Telstra CRD cooler is cracked and would never have had a fan onit. I think they are just a piss poor design.

[Rumcajs]

Problem is also the material, its too thin and constant heat expansion/contraction with vibrations finnishes the rest.

Cheers

[TaffWest]

By fixing through and therefore restricting the 2 flanges of the intercooler you dont allow for the natural expansion of the intercooler body. The stresses have to go somewhere and inevitably they will find the weakest parts of the assemly to crack.

There is a tube frame that supports the intercooler and the cover. This may be a somwhere to fix the fan to. You would have to make some custom brackets but the intercooler would be free of any restrictive stresses when expanding.

 

Ray thanks for the photos on the egt install its my next job.

[Waza]

Great tip on the loctite, my troll has the whistle too & there is some oil around parts of the cooler. I'm fitting a Dawes needle valve & EGR blank next week so I will remove the cooler & give the motor, cooler pipes a good clean & see where the oil is comming from. I feel I have the cracks as my troll is 10yrs old & 260,000 km's.

Cheers

Waza