View Full Version : Overheating problem

08-18-2007, 11:06 PM
Took the boat out for a few hours today and towards the end of the day it started to overheat. I killed the engine immediately when I saw the temp gauge peg and got a tow back to my dock. First thing I checked was the impeller--it was in good shape (I replaced it at the start of season like always). The next thing I checked was the thermostat--pulled it out and saw that it had a bunch of corrosion and junk on it. I put the cover back on and ran it without the thermostat to see if that was the problem. The temp stayed below/around 150 when I took it back out for the test run. Am I going to run into any problems if I run this thing without a thermostat in there for a few days? Thanks for the help!

08-18-2007, 11:18 PM
You should be fine. Unless there is another blockage, I'm sure you are watching the temp gauge closely now.

What was normal temp for you 160?

08-18-2007, 11:21 PM
Right around 140-150 is normal operating temp for my boat.

08-18-2007, 11:50 PM
You took one thermostat out but it has 2 (your profile shows that you have the LT-1). Check the oil cooler for blockage. If you run with no thermostats, the motor won't get to normal operating temperature, the ECM will see low temperature and run rich, sooty and it won't be very efficient. I wouldn't recommend running it with the thermostat removed.

08-19-2007, 02:12 AM
Yes, I should have clarified...I took out the 143 temp. thermostat out of the front housing just above the impeller. It still has the other one in the intake manifold. My biggest concern is not doing any damage to the LT1. The temp. was stabilized after I removed the thermostat, but I just want to make sure I am not doing anything stupid if I decide to put a few more hours on the boat before I get a new thermostat installed.

08-19-2007, 08:41 AM
You don't want to have a high temperature differential when the heads are hot after a hard run. The heads are cooled before the rest of the motor and with the 143 thermostat out, that's likely to happen. Aluminum expands differently from iron and your heads are expensive. You also can't use a 143 thermostat without the bypass holes- they tend to overheat quickly because of that.

What kind of corrosion was on the old one? Just dark discoloration or crusty and green?