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43L wonbt come up to temp

L

louiege

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"My Volvo Penta 4.3L GL (1

"My Volvo Penta 4.3L GL (1999) will not come up to temperature. Even after heavy use (inner-tubing), engine is still cool to the touch at the(intake manifold), the output hose after the thermostat is cool and soft, and the temp gauge does not go above 100F. I tested the thermostat in a pot of boiling water, and it opens per spec @ 160F. Guage (Faria) was replace, and is reading 6.3 Volts (cold) at both the gauge and sending unit. Volts drops slightly to 6.2 after the engine has run for a while."
 
I had the same issue with a th

I had the same issue with a thermostat that also seemed to test normal. Replace the thermostat & O-ring. Good preventive maintenance and cheap insurance.
 
"This is a new thermostat. IT

"This is a new thermostat. IT was the 1st thing I changed when I encountered this probelm...then I replaced the gauge just to make sure. I bought the boat used, so I've never seen it operating at normal temps (160F). Are there any other possible sources of issues other than a bad thermostat?"
 
"Besides the normal cooling tr

"Besides the normal cooling troubleshooting, from the SELOC manual here are few ideas:
wrong fuel type/octane
wrong prop or gear ratio
water intake or exhaust restrictions
air intake/carb restrictions
engine compression
fuel pump pressure
ignition timing

I have a 2000 5.7GSi with almost 900 hours. It started to run cool so I replaced the thermostat housing after 7 years along with the temp sender. It normally runs in the 150 degree range at idle in 65 degree water temp.

Hope this helps."
 
"The housing is a good lead.

"The housing is a good lead. I suppose the thermotat could be closed, but if water is still getting around it, the engine would not warm up. I'm so stumped with this isse, I've even toyed with pulling the impeller to see if this engine will ever get warm!"
 
Always a good idea to check th

Always a good idea to check the impeller. If the boat is in the water just make sure you clamp or block of the intake hose before pulling the housing apart.
 
"I've always serviced my i

"I've always serviced my impeller with the boat either on a trailer, or on the boat lift. I assume the engine compartment will flood if you pull the housing with the boat floating in the water (assuming of course the housing is below the water line). Right? or is there another issue?"
 
Correct unless you work real q

Correct unless you work real quick. But if in the water you can clamp off the intake hose; usually the top hose on the raw water pump and then you can take it apart.
 
"Louis
I had a simlar problem

"Louis
I had a simlar problem with me 4.3 last year after my impeller went bad. Try removing your thermostat housing and actually sticking your fingers in all of the holes and chambers or even sticking a scrwewdriver in there to explore. I was not able to see my obstruction, it was stuck around a corner in the bypass opening. I guess if all of the chambers and openings are not open completely the water goes around the thermostat so it doesn't get a chance to kick in.

I have pictures and water flow diagram which helped me greatly but they are too large to attach here. Send me your email if you want them."
 
I have had poor luck with afte

I have had poor luck with aftermarket thermostats. They seem to be engineered to run on the cool side to lessen the chance of overheating and engine damage. If you have an aftermarket switch to OEM. I spent 2 winters trying to get heat out of a truck and finally put in an oem thermostat after going through three others. Instant heat.
 
"Problem solved.
Chris was co

"Problem solved.
Chris was correct. I pulled the thermostat housing and was able to dig out 3 thumb-nail size pieces of impeller. These pieces were not visible from the port opening, but had to be located with a probing finger, coat-hanger, and ultimately grabed and removed with a curved hemostat. The motor now runs at 160 F!
Thanks to all."
 
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