very bad oil leak from new TA cover


Well-Known Member
I suddenly developed a massive oil leak, like a quart every 150 miles. I'm glad this happened after the 2500 mile trip I just took.

I checked the usual suspects; valve covers, oil pan, front seal etc. all were dry but the leak was coming from the front. I traced it to the bolt that goes through the upper hole in the crank sensor through the front cover. I figured the bolt wasn't sealed well since I just put on a new TA Performance front cover 2 months ago. I resealed the bolt and still had the leak!:mad:

I removed the Crank balancer and sensor and saw the cover was cracked around the bolt! When I removed the cover I placed it on a flat surface and it was almost 1/8" from being true.

I checked my old Chinese cheapo that I replaced and it was nice and flat. I guess I should have checked the TA cover before I put it on but everything else was machined so well I didn't even think to do it. It's unfortunate that every part you get for these cars has to be checked and double checked no matter who the vendor.
I've used those TA covers and they are not perfect. My last one the threads for the cam sensor bolt threads were out of wack. They are still cheap Chinese covers that have been machined a little bit. Once they are on I haven't had any issues with them.
I've seen covers hang up on the alignment dowel, and when the bolts are tightened, the cover cracks.
I've got a TA front cover & no problems with's been on for the past few seasons as well.
Since this leak just appeared, I must assume that all was good until recently. This being the case, it would seem that something has cracked the TA cover after it was installed, as it was not leaking initially.
Not sure what would make it crack & cause the massive oil leaking many miles after the install though?
Chucks' suggestion (above) makes sense, but why did it not crack initially & wait for several thousand miles before this problem surfaced? Dunno :confused:
I have also encountered a big oil leak in this same area with a Chinese cover. If I ever have to use one again, I will take the time to really go over it before installation. Meanwhile, NOS covers are what I'm using now...
I'm sure the crack developed from the stress of the mating surface being far from true. Cast aluminum doesn't bend. Nothing was done to the car from the time I put the cover on until the leak started except for being driven 2500 miles. I patched the crack with JB weld and will have the surface tried before I reinstall it.

I could see hanging up on the dowel being a problem but I'm sure that wasn't the case. I was very careful to make sure the surfaces were fully mated before installing the bolts and torquing to spec.