Is My Toyota engine being damaged by a catalytic converter w/ 250K miles on it?

I own a 95 Toyota Tacoma SR5. It is 14 year old and I still enjoy driving it, BUT, I have a slow internal coolant leak into one of the cylinders on the right bank of the engine. Periodically, I must change the spark plug, for it fouls and won't fire any longer. (No leaks at all on the left driver's side head). The head gaskets were replaced on the recall at 104,000, so I have 145, 000 miles on these gaskets.



I read recently that a catalytic converter can clog and restrict exhaust flow, creating back-pressure and %26quot;hot spots%26quot; in the cylinders, maybe the reason this one gasket failed. Puzzling how one gasket would be affected, but not both. Any ideas on that?



Anyway, my question: I have taken meticulous care of this vehicle, changing often with synthetic oil. The motor at 250K miles still does not use ANY oil between changes. I don't want to replace the head gaskets. Replacing the entire long block wouldn't cost that much more. Should I replace this Catalytic converter and put in a less restrictive one, and then try a block/ gasket sealer? I did use a product by CRC Industries with nanotechology. It held for quite some time, but failed recently. I am thinking maybe that back pressure contributed to the failure of the sealer.Is My Toyota engine being damaged by a catalytic converter w/ 250K miles on it?1995 was the last year for the 3.0 liter. It has lasted 249K miles because you have taken very good care of it. There were a lot of changes to head gaskets on 3 liter, especially on the early models(they changed the gasket 4-5 times because of repeated failures. It was not unheard of to replace gaskets 3-4 times on the same truck. They typically failed in generally the same spot in front on cylinder #1 on the passenger side but more often on #6 on the driver side rear cyl. Many factors can contribute to early failure such as electrolysis in the cooling system, clogged or restricted radiator, sticky thermostat, warped or etched cylinder head or block surface. Personally my belief like yours are hot spots (by a cooling design flaw) that causes less coolant flow at those spots mentioned, rather than a catalyst restriction. The 3.4 engine in the 96 Tacoma/runner was much more reliable and powerful and did not nearly have the head gasket problems the 3 liter had. Changing it over to a 3.4 is cost prohibitive and in some states illegal emission wise. Maybe it is time...Is My Toyota engine being damaged by a catalytic converter w/ 250K miles on it?you shouldent use sealer in your engine also if your cat is cloged up it migt have a check engine code or if the cat gets really hot like turning red i would recommend getting the head gasket fix asap though then have an autoparts store scan it for codes hope this helpsIs My Toyota engine being damaged by a catalytic converter w/ 250K miles on it?You may have come to an end. Did you change timing belt every 75,000? Converter will not do this to Toyotas as it will happen over a drawn out length of time. Block may be cracked and need new engine is most likely.Is My Toyota engine being damaged by a catalytic converter w/ 250K miles on it?250k seems to be Toyota's endurance limit, think it's time to switch vehicles. mine is now at this point, and the body is going with the engine.



@sparkbolt: this explains my pop-up oil leak (only put 30k onto it, and it started inhaling oil). I'll ckeck it out. thanks