I have done a fair bit of searching/reading, but have not found a definitive answer to my issue.

A while ago, I had a coolant leak from a head porting mishap (quite a bit of coolant was lost) and was wondering if that would cause the catalytic converter on that side to become clogged. The reason I ask is that I seem to be blowing out gaskets at the header to y-pipe junction on that side, even when I put a fair amount of Ultracopper on both sides of the new gasket.

Both mating surfaces are quite flat (and are sanded and de-greased before assembly) and I have never found that any of the three bolts at that location were loose when I went back to fix the @#$%&^ problem.

As you will see in my sig, I have SLP shorty headers with the stock dual-cat Y-pipe.

If I need to replace the cat, what brand do people like? I need to pass emissions here so it must work properly, not just be a "show" cat.

Also, does anyone have a better option than the stock GM gasket that goes at that location? They are a hassle to get here, the dealership are absolute pirates and they don't seem to seal all that well.

My intention right now is to get some of the hi-temp gasket sheet and make my own, using Ultracopper again.

Thanks for the input, gents.

 

when you say leaking coolant. do you mean that its burning coolant and you think this is clogging your cat?

 

The coolant leak was near the valve inside the intake runner and was sending a fairly large quantity of coolant through the engine and in turn, through the driver's side cat.

 

A cloged cat will eat exhaust gaskets as you will have extream back pressure and the exhaust will need to go somewhere. The motor will also lack power and run like **** because of the back pressure pushing exhaust gasses back into the combustion chamber during overlap. Your mpg will also drop like a rock.

 

I thought I read somewhere that I could confirm a blocked cat by taking some temperature readings. I have a temperature probe on my multitester which would allow me to do that.

Can anyone put me onto a how-to for that procedure and let me know what readings I should see at certain locations in order to rule out or confirm a plugged cat?

Thanks for the input.