Persistent cooling problem with Volvo Penta 5.0GL

[reggiedfw]

Motor has overheated numerous times over the last 1 1/2 years. I believe the first time was when I accidentally left out the plug where a hose is attached for running the engine out of the water.

Since then, a local mechanic has supposedly checked everything. Exhaust boots were replaced, new impeller, pumps checked (?). Thermostat, alarm, and hoses are all new.

On the water, the motor overheats consistently, slowly at low power, and faster at higher power settings. Engine becomes noticably hot, so it is not a gauge or sensor problem. Maintenance on Volvos is hard to come by in this area (north Texas).

On land, with a hose attached, cooling appears to be normal.

Am fairly desperate, and ready to jump into this myself, as there does not seem to be much good help around. Any help with on this topic would be greatly appreciated.

 

[Don S]

Re: Persistent cooling problem with Volvo Penta 5.0GL

Are you sure that hose you left the plug out of has a good gasket and seal. If it leaks air, it WILL overheat.

 

[captmello]

Re: Persistent cooling problem with Volvo Penta 5.0GL

I've got a similar issue with my 350. Does the motor cool down fairly quickly when you back off the throttle? Check that cap like Don said. You may want to try the clear hose method. Clear hose from thremo housing to one or both manifolds and look for air bubbles. Boat must be in the water. Check at Idle and while cruising. Don't over rev the engine in nuetral. This can tell you if your getting air in the cooling system and go from there.

Most overheating problems won't happen on muffs unless it's really clogged up. I suppose you've drained your manifolds and block to check for sediment, sand, rust etc.

A badly tuned motor with a badly adjusted carb may overheat. Does the motor run good otherwise. Your getting around 4500 RPM @ WOT?


Let us know what you do and we'll walk you through it. What year/outdrive?

 

[CharlieB]

Re: Persistent cooling problem with Volvo Penta 5.0GL

Compression test
and
Cylinder Leak Down Test

You need to test to verify the head gasket seal.

The original overheat may have cost you a head gasket, causing subsequent overheating.

 

[texsun]

Re: Persistent cooling problem with Volvo Penta 5.0GL

I've been checking on your post for the past few days. I agree with Charlie in that it is worth a compression test. I'm pretty sure you can rent the item at AutoZone. Although there are several things that could be causing the issue...I think you have to find out if combustion heat is getting directly into the cooling jackets(leaky gasket). The combustion test on each cylinder will answer that question. Your post led me to believe that you had already looked at the more obvious(and less expensive) items and it has continued to overheat. The overheating can and will lead to blown headgasket.

Good Luck!

 

[artificialreef]

Re: Persistent cooling problem with Volvo Penta 5.0GL

Blown head gasket usually shows up with foamy oil on the dipstick jimmy. Are ya usin yur dipstick (sorry, I love that commercial) After overheating that many times I think a warped head is a distinct possibility. Compression test will give you an answer. Not hard to do for the shadetree mech. I did one before I bought my basket case. Although I broke 2 out of the 8 spark plugs doing it. The caretaker didnt seem to mind.

 

[artificialreef]

Re: Persistent cooling problem with Volvo Penta 5.0GL

Oh yeah, forgot to mention. Use compressed air to blow out the plug cavaty and use antiseize on the replacement plugs.

 

[artificialreef]

Re: Persistent cooling problem with Volvo Penta 5.0GL

That is, use the compressed air before you take the plugs out, if your really new at this. (to blow out all the garbage that has accumulated there in that little vally) If not it will all fall into your cylinders for your rings to enjoy.

 

[stackz]

Re: Persistent cooling problem with Volvo Penta 5.0GL

Blown head gasket usually shows up with foamy oil on the dipstick jimmy. Are ya usin yur dipstick (sorry, I love that commercial) After overheating that many times I think a warped head is a distinct possibility. Compression test will give you an answer. Not hard to do for the shadetree mech. I did one before I bought my basket case. Although I broke 2 out of the 8 spark plugs doing it. The caretaker didnt seem to mind.

or the deck surface could be warped...

I've seen head gaskets blow out just the fire-ring and never reach a cooling passage so you can obviously have a blown head gasket without getting chocolate milk in the pan...though this is more common