2003 Glastron VP 5.0 GL Overheat issue

i_build

Petty Officer 2nd Class
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Apr 24, 2005
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151
She got hot after a short run 180* right at the dock on the way back in so I shut her down right away. Never got hot before and I got her at the end of last year and put about 30 hours on her since. I just replaced the T-Stat and that didn't fix her. Even on the hose after about 10 mins she climbs to 180* and I shut her down so I am thinking circulating pump and manifolds and risers. The manifolds and risers say Volvo Penta on them but darned if I can find a cross reference or anything on them and I dont want to order the wrong ones. I see 3852564 but I cant find anything that matches or cross references to that and all the ones I am seeing on Amazon dont have that number as one that they replace. The riser seems to measure out at about 8" and I would think if they say 5.0 GM fitment the manifold "should" bolt up but I don't know if there are that many different types out there. I would probably get local if I could but I need to finance these and have credit on Amazon cause it isn't in the budget but attached also is the Amazon ad for what I was going to buy. I have the circulating pump already but I don't know if it is possible that the overheating may just have been caused by that alone being bad? Please help me get this squared away... and just to level set... no way I can afford OEM I just dont have it... 1756159906301.png
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ESGWheel

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There are many things that can cause an overheating situation. They range from the intake hoses in the sterndrive are sucking air, to the Raw Water Pump (RWP) (aka seawater pump) not working properly to T-stat, to blockage in the output, etc.

So before jumping to the conclusion that it’s the manifold and risers, need to do some investigating.

I would start with the RWP and pull it apart and evaluate the impeller as well as the chamber. Is the impeller intact? Does the chamber it sits in have any groves? Suggest getting a RWP impeller kit and change it out as you do not necessarily know when the last time it was changed. This is different from the “circulating pump”.

Google about how to change the impellers, you will find lots of videos, it’s easy to do.

Also, no need for OEM manifolds and risers but I would shy away from any aftermarket other then Barr. Will be about the same price as your AZ special.
 

i_build

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Sorry I forgot to mention that I did do the raw water pump at the start of the season. I was thinking that with me having replaced the raw water pump and also with it overheating while using the volvo pentas feed line (blue capped hose at the engine) with direct hose water pressure it would be less likely that it was air infiltration from the hose from the pickup running from the drive. I have not changed the circulating pump though. I have a new one to install to see if that somehow is the cause. I wasn't sure whether running from that hose with strong water pressure in from the flush line is enough to say that if it overheats still the issue is the manifolds and risers. I used a laser thermometer and confirmed the temp at the the thermostat housing matched the 180* showing on the gauge, down by the raw water pump the hose was 100* the risers were close to 180* even on both of them.
 
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ESGWheel

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OK, so let’s reset and start at the beginning: a new to you boat and had 30 hrs last season of no issues. What changed? Ie did you do an impeller replacement and now it overheats? Please provide in chronological order what was done (maintenance wise) and when started to experience overheating.

Also running on the blue capped hose should be ok if you are at idle or slightly above. That connection is not made for steady state running at 1000s of RPM. Does it overheat on the hose at idle? Do you get a good flow of water out the exhaust when running on the hose?

Also consider getting the needed riser / manifold gaskets > pulling them off and inspecting them may show still ok for a season or two. Depending on use (salt or fresh) they probably need replacing but due to about to leak vs. the cause of overheat.
 

i_build

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I purchased late last year and before my first use I replaced the bellows and gimble bearing, lower unit lube, oil and filter, plugs and dizzy and the entire raw water pump including impeller and housing. Did about 30 hours without a hitch temp always below 170. Just before the last trip out at the dock I put in a new filter / water separator drove out 15 mins no problem back 15 mins no problem pulling back into the dock saw the temp hit 175 for the first time and shortly after the buzzer went off. I cut the engine and coasted to the dock. Next day went back and swapped out a new thermostat. Tested the old one that looked bad but it seemed to open at 160*. Went back to the dock to test the thermostat install on the work rack on a hose connected to that blue fitting and idled for about 10 mins before the alarm went off again. Used the laser temp to check and the manifolds were both even at about 180* so was the thermostat housing but when I pointed down to the raw water pump it was at about 100*. Tilted the drive up to see whether the hose for the water maybe worked loose or broke and it looked in tact. Only recent change (just before the last trip) was the fuel filter. Not sure whether it not being seated right could cause it to go lean and overheat? Would have thought it would leak before that... but my nephew did say he smelled fuel and I thought maybe I spilled some swapping in the new one... could that cause an overheat issue on a carbed engine?
 

Scott Danforth

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I do not see where you replaced the raw water pump or looked at the cooling line fitting on the drive
 

Lou C

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If you tested the 'stat, it is open by 160*, correct, and you're sure the raw water pump is good (including the wear plate, if this is scored even a good impeller won't pump properly) then the next thing I'd do before replacing the whole exhaust system is drain out the water and remove the exhaust elbows to see how clogged the passages are in the manifolds and elbows. Sometimes you can rod out the passages in the manifolds and re-surface the mating surface and just replace the elbows instead of the whole system, but it can be risky. I do see rust seepage at the joint between the 2. Volvo had trouble with the original gaskets and revised them and published instructions on how to properly resurface the mating surfaces. 180* on your stat housing and exhaust elbows or manifolds is definitely too hot. I have an old '88 OMC Cobra and the impeller is different but the rest of the system is just the same as the Volvo, and the stat housing (top part) will be about 135*, the intake manifold right below the the stat housing will be about 145-150 and the manifolds/elbows will be between 95-110 at idle, the hottest they get is about 135 and that's only after coming off plane, they will cool off pretty fast after idling a while.
If you haven't done it, make sure all the passages in the stat housing are open, these will get restricted with rust just like your exhaust system and if you don't have good flow to each manifold they will for sure get hot. Just rod them out with a coat hanger wire.
The other thing unmentioned here is the path of raw water on the engine, you can have clogs in your water intakes on the outdrive, not common in fresh water I guess it but is here in salt water (marine growth), there is a copper tube that transfers water from the lower unit to the upper unit and the grommets for these can wear out/soften and then you don't get full water flow to your impeller. I would test the output of the raw water pump and see if you're getting what you should in terms of volume. If the grommets for the water tube are leaking internally then you have to split the drive to replace them.
If you have to replace the exhaust system do NOT buy off brand stuff from Amazon, if that joint between the elbow and manifold leaks because of poor machining of the cast iron you will have water in your cyls and a possibly ruined engine. People used to have a lot of trouble with GLM exhaust because of this, they might be better now, but I heard bad things about them from a marine mechanic I know well and a guy I get my parts from won't even order them. The only aftermarket I'd use is Barr Marine. I installed a set on my Cobra 8 years ago and they are still good (this is good for salt water use!) and it all fit right with no leaks. And you definitely should check the flatness of the mating surfaces with a straightedge and feeler gauges (less than .003" variation).
 

Scott Danforth

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I will also add, the chinese amazon specials that you have listed are more expensive than Barr manifolds which are OEM quality. I only recommend Barr or Osco. I do not recommend amazon chinese manifolds.
 

Lou C

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Check out Lighthouse Marine in Riverhead Long Island that’s where I got my Barr exhaust. I can save on shipping (heavy!) because it’s about a hr drive from where I live. But first see what you have. If this boat was used in only fresh water the system night only need cleaning of the passages and re-surfacing of the mating surfaces w/new OEM gaskets.
 

i_build

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I do not see where you replaced the raw water pump or looked at the cooling line fitting on the drive
I did replace the entire raw water pump and impeller at the very start before I put her in and I did inspect the cooling line that I had to remove when I did the gimbal bearing and it was clear and in good shape when reinstalled. I also checked it yesterday with the drive tilted up. I used to go to Lighthouse Lou back when I lived in Brooklyn and I did use a Barr for my Anna Capri so i will start looking local if I cant find it on Amazon. The boat was "supposed" to have been fresh water only till I got it... but the PO mentioned some things that weren't exactly true that I found out after purchase so I take it with a grain of salt.

The T Stat housing did look fairly clear of build up or rust when I replaced the T Stat

I did get the whole Raw Water pump off of Amazon... and I wouldn't think 30hrs of use would trash it... but I will definitely check the impeller condition before moving forward and do a test for flow to make sure no obstructions or air leaks from the drive up (using a clear hose between the RWP and T Stat housing and checking for bubbles). The manual also says if I disconnect the hose from the RWP at the T Stat housing I should see a rise of water 2-4" inches holding the hose vertical... If that's in good shape... then I will pull off a riser and have a look. It's my wife and I only escape and she is a double organ transplant recipient so every day is a day we love to be on the water so we are kind of sad since all was beautiful up to now.

The benefit from me getting the stuff from Amazon is the tight budget right now and them letting me finance it 0% interest... but I also don't want to slap junk on to have issues sooner than later... that's why if it looks like rodding it to clear it might help... I will give it a shot for the short term... but I would probably just opt to find new ones longer term. That rust between the riser and mani has been exactly the same since purchase and I have checked for any moisture after each trip and have seen none... but I wouldn't put it past understanding if it was original 2003 stuff... so for peace of mind if it comes down to the manis and risers I will shop for the Barrs... I didn't see them on Amazon but I might have missed them.

Going to head to the marina after work today and start... will post some updates and more pics. Thank you for all of your help.
 
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Lou C

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If you can find this document it might help:
Volvo Penta Overheat Diagnosis; is explains exactly how to solve overheating issues via testing & process of elimination. If you can find it I think it will help a lot!
If you used an Amazon impeller I’d replace with OEM. I always use OEM for critical parts like impellers & bellows.
I wouldn’t be surprised if the passages in the manifolds & elbows are clogged. Some time with a coat hanger, & mill bastard file to carefully resurface the sealing surfaces and a thread chaser to clean the threads may be all it takes. These open cooling systems are by their nature more prone to problems than a closed system in a vehicle . You need lots of cool water IN and warm/hot water OUT; anything that gets in the way of that will cause overheating.
 

Scott Danforth

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I did replace the entire raw water pump and impeller at the very start before I put her in and I did inspect the cooling line

I did get the whole Raw Water pump off of Amazon... and I wouldn't think 30hrs of use would trash it...

The benefit from me getting the stuff from Amazon is the tight budget right now and them letting me finance it 0% interest... but I also don't want to slap junk on to
recheck the raw water pump. only use Johnson impellers or get them from Volvo Penta. do not use Amazon impellers

only use GM raw water pumps. most of the amazon ones are not marine. they are cheap automotive ones with steel impellers

do not use amazon for junk manifolds
 

Lou C

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I looked again at the pic of the manifold/elbow joint & you can see moisture oozing out. Def a problem there! You don’t want clogged elbows etc but also if they are leaking on the inside that can put water in cyls; rust exhaust valves etc.
 

i_build

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If these thunderstorms quit for a while I am going to get sea tow to take me dock to dock from the marina to my boat ramp so I can put it on the trailer and take it to my driveway where I have access to all my tools. I see what you see Lou so I will pull the risers off and take pics... and no matter what... get a new impeller like Scott recommended. I still have the original VP Raw water pump housing that I replaced with the Amazon one... so I will inspect that and if in good condition use the new impeller on that and swap it out the entire Amazon one with the original VP raw water pump and new Johnson or VP impeller. I did purchase a circulating pump from Amazon but it says it is made in USA, and is OE Mercruiser with Bronze impeller... I paid a little more... but I "think" this one is safe... Might as well cover all bases. Will update a little later thank you both I appreciate the help.

Yep my eyes are not what they used to be... I do see drops on that Pic.
 

Lou C

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When you take ‘em apart goggle VP elbow gasket replacement; they came out with updated gaskets & instructions to use a copper based sealer. Also forgot to mention that if they look good the manifolds should be tested for pinhole leaks by propping them up level and filling with Acetone instead of water. The Acetone will find pinhole leaks that water won’t (not when they’re just starting). Be careful though because it’s flammable. The Merc water pump from Amazon should be fine as long as it’s genuine. I have used Sierra for the circulating pump in the past without problems.
 

i_build

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When you take ‘em apart goggle VP elbow gasket replacement; they came out with updated gaskets & instructions to use a copper based sealer. Also forgot to mention that if they look good the manifolds should be tested for pinhole leaks by propping them up level and filling with Acetone instead of water. The Acetone will find pinhole leaks that water won’t (not when they’re just starting). Be careful though because it’s flammable. The Merc water pump from Amazon should be fine as long as it’s genuine. I have used Sierra for the circulating pump in the past without problems.
Thanks... I did that acetone test with the Anna Capri and that was what clued me in to needing a replacement. Been looking for someone that has the Barr manifolds and risers for my engine local to Tampa. Have a tow scheduled for tomorrow and will have her back in my driveway tomorrow night. I am planning on just installing the new ones cause we really dont want to risk it. Thanks again will post updates as I go.
 

ESGWheel

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Sorry for the delay. Looks like you are in good hands with Lou and Scott. Here is some tips and tricks on the risers and manifold removal, replacement, see post #18 of this thread link. Also, I have put in the Barr product and been happy with it.

And nice follow up with the explanation of your issue, this is the kind of info needed for folks to properly help, so appreciate your detail. It is also clear you are taking good care of it even with the budget constraints. I totally get the desire to be 100% confident in the boat to enjoy the relatively few hours we do have with them.

To answer the question about can running an engine lean lead to overheating. Short answer is yes. Longer answer is not in your case as outlined: a not fully tightened fuel filter sucking air and thus ‘starving’ the engine of fuel. Recall that that carb has its own reservoir of fuel (float bowl) so it would have to go empty to go lean and you would have experienced much different symptoms before overheating.

Good luck and please post how it goes or other questions.
 

i_build

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Thanks Lou I found this on another site

The service bulletin indicates:

Change to Procedure:
Before installing a riser gasket, coat the mating surfaces of both the manifold and the riser with a copper-based, heat resistant gasket compound.
Examples:
Permatex Copper Spray-a-Gasket® (80697)
K&W Copper Coat® (401612)

Also found the Barr Mani and Risers here

A little over 1119 + 50 shipping... and also there's an option to pay using Amazon so hopefully at check out I can use the instalment plan. I haven't placed the order yet because I just got the boat in the driveway and there are 2 different exhaust sizes 1 is 4" and the other is 3 3/4" so I need to measure to see which ones I order. Will pull a riser tomorrow and post pics also.

Thank you ESG as well the link you posted is helpful I appreciate it
 
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