Ran at just over 210 deg (230w/trailer)with leaking water pump, replaced water pump and thermostat but it didn't change temp problem. Then changed out radiator and re flushed system and it still runs hot but wont overheat? It stays just over the 200-220 mark but it should be runnin at 190, upper hose stays real hot, whats my issue?


1994 ram 5.9l

 

Are you losing any coolant?

Sure you got the right thermostat? 195 degrees. Did you check to make sure it opened by dropping it in a pot of boiling water?

What's the lower hose feel like?

 

did you flush the block by removing the drain plugs. my 01 has hex head pipe plugs on each side, hiding behind the engine mounts. mine were sort of hard to get out, because i couldn't get either a socket or a wrench on them straight, and so they tried to round off. i eventually used my best vise grips to break them loose. so if you do this - treat them with penetrating oil beforehand, especially on a 94 that may have never had them off.

anyway, a lot of heavy sediment came out of mine.

 

Hate to say it but you most likely blew a head gasket or cracked a head when it got hot while towing. Also is your plenum leaking? Are your O2 sensors working correctly?

 

not loosin any coolent n I put a new one in and u can tell wen the truck starts heatn up wen it opens cuz it heats up to like 230 then drops suddenly to just over 200, lower hose is hot also

 

I didn't flush the block wasn't sure how to do it, after the plugs are out just run truk with hose in the radiator to flush? ill try that

 

Sounds like your thermostat isn't working properly. It shouldn't be going to 230 before it opens. Put a Stant superstat in there and see if that doesn't help.

 

What does the lower hose feel like? It should be significantly cooler than the top

 

assuming you have new coolant in there, drain radiator to save it. flush block with water hose, either from from the top through the tstat hole or through the bottom radiator hose. make sure clear water is coming out both sides, not just one. i don't think running the engine would do anything different from putting the hose in it for several minutes.

if this doesn't help, you should investigate the possibility of head gasket problem. like arde said, temp should not spike up. it should just heat up to the 195 target and simply hold there.

another question- from a cold start, with radiator cap off to relieve any possible pressure build up, does the temp spike up to 220, or act more normal. this would be evidence of compression leak.

 

Might just be air as well. Drive it for a bit. let the engine get nice and warmed up. (but, don't overheat). Let the thermostat cycle a few times. it should straighten itself out.