Overheated Volvo Penta 5.0 GL

[mikeneal]

I over heated a 1999 Volvo Penta GL last week and was wondering how badly I might have hurt it. Bear with me and I will tell you the details, it will take a while. The supply hose from the raw water pump (crank mounted) came off at cruising speed and by the time I realized it it had burned the riser connection to the down pipe and really toasted the hose to the Y-Pipe. Just on the port side of the boat though...weird. Engine make ugly noises and deiseled when we finally shut it off. Anyhow the pump did a fine job of filling the bilge with water and plus the Y pipe connection was leaking water into boat. Took a second to figure out what the heck happened. Though she was sinking for sure, way scary. Anyhow towed the boat back to shore and started it up on ear muffs to see how badly it was hurt. Ran OK for about 15 seconds then missed couple times like it was dropping cylinders and finally hydralocked. I removed the plugs and water came out of the port side (starboard was OK). Oiled it down good with WD 40 and left till I got home from vaction (we were 3 hrs away on a long boating weekend). Got home and pulled the riser off the port side . Did compression check and it was 175-200 on all 4 cylinders with water ingestion, about 160 on other side. Weird huh, I am thinking maybe because of the WD 40 taking up volume at tiop of compression stroke? Anyhow could not find any cracks in riser so replaced riser gasket and hoses and started it up. Ran really roough at low speeds. The heat burned a couple ground wires and trim hoses so I thought maybe it killed plug wires too. Did a cap/rotor and wires and repleaced power valve too while I was at it. Ran it for about an hour total and never could get it to hydralock or over heat. Oil in crankcase looks fine. I am changing it anyhow tommorrow. I cannot put boat in the water because I have not fixed the trim hoses yet...I think the gimbel housing must be removed..joy. The boat runs rough and acts like it loads up when idleing on the ear muffs and sounds like it is low on power when you rev the motor. Hard to tell with no load though. Did a second compression test when hot to try to see if head gasket needed to be hot to leak and all cylinders read from 160 to 170 psi. I know same is good...but any clue what is normal for a 5.0 liter small block GM motor? What are the odds I got lucky and the boat major motor parts will be fine? What could I done to make it run badly? Anyone have any experince with overheating them so darn bad they burn the exhaust off and the motor is still OK? Thanks for your support. <br /><br />Mike

 

[mikeneal]

Re: Overheated Volvo Penta 5.0 GL

Opps I forgot , the flapper on the port side was totally gone, just the shaft left. My local dealer said VP stopped using them and to just forget about it, anyone ever heard of that? I am worried about a wake hitting back of the boat and hydralocking it. Could a piece be in my exhaust, causing my power and rough running issues? I am thinming tomoorow I will pull the drive and see if I can see it.

 

[Northern Eclipse]

Re: Overheated Volvo Penta 5.0 GL

Compression sounds alright but do a leakdown if possible, exhaust flapper must be found, also check impeller in belt driven pump, could be toast also since ran dry, has far has not using flapper I cannot comment but if its made to have one, then I would replace also. As far has motor goes, it all depends on how hot and for how long it was hot, but if exhaust ran dry it doesn,t take long to burn up the rubber components, so you may not have got motor to hot to hurt it.

 

[Rickles]

Re: Overheated Volvo Penta 5.0 GL

I had one in the shop recently that burned the paint off the elbows and melted the exhaust hoses and it turned out ok.Find the melted flapper and replace them with both.Volvo in their great wisdom decided that flappers are'nt required but don't believe it.Replace them and check out your water pump impeller also.If it got that hot it's toast.Look for all/most of the pieces to avoid blockage of passages.Some may be stuck in the t-stat inlet causing a restriction.180-190 psi is normal for a new engine so 160-170 is ok.

 

[mikeneal]

Re: Overheated Volvo Penta 5.0 GL

I found the flapper (it was a melted biscit at the outdrive-gimbil connection). Any clue where I can get new ones? My two local VP dealers say they cannot get them from Volvo, as they were disconntinued. Now I am working on removing the gimbel /bellhousing to get at the trim hose manifold to replace the two trim lines I melted. Then I guess I will just put it in the water and see what happenes. Thanks for your input/advice.

 

[Dunaruna]

Re: Overheated Volvo Penta 5.0 GL

Mike, I don't know if this is relevent to your model but exhaust bellows are available for VP with built in flappers.<br /><br />Aldo