Of course this happens while I am about 8 hours away on vacation, my son just called and said that the temp guage went up all of a sudden on his 02 and it started missing. This happened once before and it turned out to be a stopped up catalytic converter. I believe that was around 40k miles and it now has around 80k on it. Are catalytic converters a real problem on these cars? Isn't the warranty on the emissions system 100K? I sure hope so as I would hate to have to pay for one when it seems like GM just can't get there act together on this. In my previous job I drove a 04 GMC 1/2 ton pickup and it had the catalytic converter stop up at around 40k miles. If I do have to pay for another converter, I guess I will just break down and trade it for a decent Honda as that is what my wife and step-daughter drive Hondas and we have had no where near the trouble out of them as we have out of the Monte Carlo.

 

Every Cat. that I've seen that was plugged has over 115K on it. This is the first I've heard of anyone having that problem with so few miles. I'd say to change the place you getting fuel. Bad camel **** fuel.[:'(]

 

May not do you any good but I'd check into this anyway. Mine was replacedfree at108K. https://montecarloforum.com/m_12459/tm.htm

 

It appears that it is something else. He stopped and added water to it and made it to the house before the temp went up again. He said that there was steam coming out from under the hood so it may be something as simple as a hose. I hope that it is not the lower intake gasket again. I have already changed that and it was not fun. As usually happens when something goes wrong, we are on vacation and won't be back until Saturday night so I can't look at it until Sunday.

 

Its possible to drill a tiny hole before the cat and measure psi, drill one after. Significantly higher psi before cat than after indicates a clog. Do a google search on how to test a cat you'll see the video. Also cats will clog up if subjected to more fuel than normal, or oil because it forces the cat to work harder. Only reason I know this is the reason why I even own a MC. My Lincoln Mark VIII has 2 plugged cats that I ignored, both 02s got fouled up, and eventually I blew my egr tube causing me to overheat. Good luck

 

When I got back into town I found two problems. His themostat was stuck closed and there was a leak where the plastic tank is attached to the core. It was going to cost half the price of a new radiator to get the tank replaced soI just bought a new one and a new thermostat. The guy at AutoZone did talk me into a failsafe thermostat that will stick open if it fails. I never knew they made one that way and it really makes sense. All thermostats should be made that way.

 

How much was the fail safe one? I know the standard ones are $10.

 

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