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Volvo Penta 43 running cold

S

schadow

Member
"I have a 2000 Volvo Penta 4.3

"I have a 2000 Volvo Penta 4.3 in a Glastron runabout. My water pump went out last year and the local marina replaced the impeller. Ever since then, the engine will only get up to just over 100 degrees when running, normal is roughly 160 - 190. I believe the gauge is right because I can touch the engine after running and it is clearly not hot. Trying the simple fix, I replace the thermostat and this made no difference. When I installed the thermostat I made sure the spring side was pointed towards the engine block which is how the old one was mounted. I thought this was a pretty simple system, I guess not. What other things can I check?? The engine actually runs pretty well but will back fire some on cold mornings at mid range RPM’s. Not a big deal because I am mostly a summer boater. If I leave this situation can I damage the engine long term?"
 
I would start by verifying the

I would start by verifying the temp. with an infrared or laser scanner. If this confirms the gauge reading I would remove the tstat housing from the engine and inspect it. If your raw water pump 'went out last year' there is a chance a piece(s) of rubber from the impeller is lodged in the housing and allowing water to bypass.

Also ensure that your hoses are routed properly on the housing and heat exchanger. Good luck.
 
I just had the housing off las

I just had the housing off last weekend to change the thermostat. Other than a little more corresion than I was expecting it was clear. On that model engine all of the hoses are different sizes so I it would have been obvious if the hose were switched around. I will still have to verify the actual temp. I assume an auto parts store will have a infrared or laser scanner? My primary concern if long term motor health.
 
"I had this problem with my 5.

"I had this problem with my 5.0 GL volvo. I changed the thermostat, sender, etc and it still ran cold. The problem was that the bypass port in the thermostat housing was plugged. You cannot see into the housing to know it is plugged but I have now found several other people who have had the same "cold' problem and the problem has been a plugged port in the thermostat housing. You may want to pull it off again and push a wire or screwdriver through to make sure nothing is plugged. You can also put a hose to it and insure water is coming out. The bypass is a very small hole in the casing. Hope this helps."
 
Thanks Jerry
Where in relatio

Thanks Jerry
Where in relation to the thermostat & O ring is this hole and are we talking the diameter of a pencil? bigger/smaller?
 
"You have to pull the thermost

"You have to pull the thermostat out to get to the hole. It is above the O ring seat about in the middle of the housing. The size is about 1/4 inch. Depending on how clogged it is, you need a coat hanger or 12 gauge wire to push through. The tunnel is not straight which makes it hard to push a screw driver through. On mine I was able to force a small flexible screwdriver through the hose side into the housing. I had to work and turn the screwdriver many times to get the clog to break free. I am a member of Seloc online and was able to get an exploded view of the cooling and exhaust system which shows a detailed view of the passages both warm and cold. Web page was: www.selocmarinel.com/content/manuals/3606/images/full_36069g26.jpg"
I hope this helps.
Jerry"
 
I have the printed stuff at ho

I have the printed stuff at home. I will try to scan the information into a PDF file and post it either tomorrow or the next day.
Jerry
 
I cannot attach the files here

I cannot attach the files here because the size is too big. I will send them by email.
Jerry
 
"Thanks Jerry, you were right

"Thanks Jerry, you were right on the money! A piece of last years burned out pump immpeller had lodged into the bypass port of the thermostat housing. Fairly difficult to extract but after I pulled it out engine temp went to normal again.

Thanks again!"
 
"Guys, Thanx for posting this

"Guys, Thanx for posting this information. For more than 2 years, my engine has been running cold. Ever since I had bought my 1999 FourWinns Volvo Penta with the engine replaced no one could figure out why its been running cold. The thermostat has been replaced 3 times, the temp sender once. Its been a constant concern that something was wrong but no one could help. After running the boat this past week, I once again got frustrated with why it was running cold. I was ready to take it to get it serviced AGAIN, but decided to search the web AGAIN. Well lucky me, I found this post, took off the thermostat housing, and found pieces of the pump impeller lodged in the port. And your right, surprisely, it was quite difficult to get them to dislodge. Just wanted to say thanx again for posting and helping me out!"
 
"Hey ireckonso
This message b

"Hey ireckonso
This message board saved me too, Now I regularly come back to see if I can help others. Engines don't need to be that scarey!"
 
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