after pulling my 440 several times last winter to stop rear main seal leak, I noticed some sealer getting pushed into heads thru exhaust bolts. I started to have high temp probems this summer.Replaced water pump and thermostat,still running higher temps than normal. Where could the pieces of sealer be stopping up cooling system?

I use anti sieze on the exhaust bolts and never had a leak.Try pulling the 2 plugs on the bottom front of the block and see what comes out.You cant believe how much gunk gets built up down there.Most plugs Ive pulled water wont even come out till you get the crud out of the hole.Rocky

The dirt and crud behind the soft plugs is really what rusts them out - not the coolant moving past them. Most of the time when you pull them the mud is way up on the freeze plugs. The truly best way to flush an engine is to pop all the plugs out. Just flushing with moving water will not get most of this out.

More info, started getting hotter all of a sudden or gradually this summer. How hot? around town/idleing or out on the highway? Have a shroud? rad marginal? any other driveability probs when it started happening

Started this summer early. Has original gauge in 65 belvedere. In past never got above 1/4 on gauge,Now gets gradually warmer highway driving. In town or idleing moves up past halfway to about 3/4. Has shroud, Car had dealer installed air and has bigger radiator for air conditioning. All started after sealer got into cooling system from exhaust bolts. After pulling engine several times to get rear main seal from leaking. I also replaced water pump and thermostat, no change. I believe there were pieces of sealer about the size of the head of a pencil that got into system. I wonder if they would be pluggingthe cooling sysem anywhere.

Unless they are a few thousand floating in there I doubt they can plug anything up.They would all have to be in one spot pretty much.Pull the plugs on the block and do a good back flush there and on the rad.Rocky

It doesn't take much to plug a lot of the radiator tubes with gunk. You could pull the radiator flip it upside down and flush it out real good. That would eliminate it as a possible cause...?

Thanks for the suggestions, your help is appreciated.

update: I pulled radiator turned upside down and flushed, a few pieces of sealer came out. Took car for test ride,seemed slightly better but still got warmer than usual at low rpm. Engine onley has about1000 miles since rebuild. Block and heads were cleaned and flushed. Running flex fan. Used to be higher rpms would get warmer then cool down as rpms got lower. Now is just the opposite.

Yeah me too! Flex fan? radiator cap?