Hyundai Elantra Forum banner

1 - 5 of 5 Posts

·
Registered
Joined
·
42 Posts
Discussion Starter #1
My P0420 CEL code came up again after replacing my downstream O2 sensor a few months back. There has been no diminished engine performance, but my gas mileage was really poor 18-20mpg combined. Also an oil leak has flared up in front of the cylinder head by the valve cover. Even though I replaced the valve cover gasket a few months back. The oil seems to be coming out of the front valve cover screws and a few cracks in the cover. I just changed the oil last week, 5w-30 Mobil 1 full synthetic.

So before buying a new cat/exhaust manifold, I decided to clean the PCV valve figuring there was a positive crank pressure in the cam area causing the leak. My PCV valve like so many other on here complained about, would not screw off from the brass housing and the whole piece came out with the threads, I sprayed it with brake cleaner and stuck it back in. I changed my engine air filter after about a years use and reset the ECU taking off the battery cables and taking out the fuses. Its been about 100 miles since my last CEL, fingers cross seems to have worked. Improved MPG this weekend and I'm thinking about JB welding the valve cover cracks, never used that epoxy before. Anyone have experience with JB Weld on plastics?
 

·
Registered
Joined
·
179 Posts
I don't know which will work better, or temp ratings on either, but they do make a JB Weld for plastic. Both work really great.
 

·
Registered
Joined
·
42 Posts
Discussion Starter #3
I don't know which will work better, or temp ratings on either, but they do make a JB Weld for plastic. Both work really great.
Thank you, I ended up getting the original. It says it is temp rated to 550 degrees, I don't think the valve cover gets that hot. Hopefully the pcv is working and it won't create any more cracks
 

·
super dog
Joined
·
48 Posts
Regular JB weld will do the job as long as you start with a clean surface and give it time to cure. I used it on a cracked dirt bike bottom end and it's still perfectly fine 7 years later.
 

·
Registered
Joined
·
988 Posts
It's better to replace the valve cover, gasket and pcv valve altogether. Using glue is like putting bandages and the problems may keep coming up.
 
1 - 5 of 5 Posts
Top