Logo
FULL SITE MENU

Overheat at idle speeds

S

scottyz

New member
"I run a pair of Crusader 5.7

"I run a pair of Crusader 5.7 320 HPs with 425 hours..FWC. At 3000 RPM, the port engine temp is 170 but when I throttle back to idle or slow speed it climbs to over 200. I have strainers which i clean. I repalced the raw water impeller twice. I had the end caps removed from the heat exchanger and flushed out bits of an old impeller and there is plenty of flow. It seems that there is little or no water coming out of the exhaiust port during idle speeds. The riser was checked. I also flushed the entire cooling system out with RYDLYM. i am running out of options and funds. Any thoughts would be appreciated.
Scott"
 
"I thought about the thermosta

"I thought about the thermostat, but wouldn't the problem exist at any speed? I am not a tech by the way."
 
I had a similar problem and di

I had a similar problem and discovered that the raw water pump drive belt was slipping. It has to be pretty tight.
 
We have probably all had simil

We have probably all had similar symptoms. I did in 2002 on a 454 CID. As it turned out the impeller was good but the sand in the mighty Mississippi River had ground away enough of the pump body that it lost efficiency. It doesn't take much to alow internal bypassing. The damage is not visible. The body was as smooth and shiny as could be. Surely you have a whole spare pump. Install it. If that is not the problem then go the the next thing to check. If you don't have a spare you need one.

I agree that a little air in the suction will give the same symptoms. It also results in cavitation in the pump and results in eating up impellers. Sounds like the engine has been through at least one since you dug pieces out of the cooler.

Chuck Hanson
 
"Chuck, my mechanic thinks it

"Chuck, my mechanic thinks it is the raw water pump, which he is changing out. Good call...I hope.
Scott"
 
Back
Top