5.7 gla AFTER OVERHEATING CHECK LIST

SeaLord

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Oct 29, 2013
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47
Hi all
I am currently in a country it is not easy to both have a proper diagnosis and spare parts. So before I order anything I need to have a pretty good idea of what I should get.

My volvo penta (around 100 hrs lake water) boat was tested after a long journey in a container. Annual maintenance done on both the engine and the sterndrive. Since I bought used before shipping it I also change the thermostat. To my surprise (inspector reported that boat was positively tested in and out if the water) i found the TH gasket melted.
I started the engine out of the water putting a barrel so the inlet in the outdrive where submerged. in 5 minutes the engine overheated(240F) and the alarm went on. I let it for 10 minutes and the started again but temperature was still very high.
I was alerted that probably I should not have run it in the barrel. According to this overheating came from the raw pump not been able to provide enough water.

I have since pulled out the thermostat and saw that the gasket was completely melted. Therefore the overheating was real (not a misreading by the sender). This may be serious so I need to know what to check in order to have a most likely list of spares I need to order: What are the possible damage in the engine, raw water pump etc. and I do I check there is likely a damage without disassembling everything ?
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
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Re: 5.7 gla AFTER OVERHEATING CHECK LIST

dont forget the exhaust hoses from risers to your transom y-pipes. those also tend to not like to be heated up.

do a compression test as well.

not knowing which outdrive you have, a barrel is not a substitute for a proper set of muffs to get water up to the raw water pump for priming when the boat is out of water.
 

SeaLord

Seaman Apprentice
Joined
Oct 29, 2013
Messages
47
Re: 5.7 gla AFTER OVERHEATING CHECK LIST

21213660 Impeller kit.
3856961 3852071 3852111 thermostat and o-ring and gasket.
Your motor is 12-13 years old.
Been in salt water?
If so you might need manifolds and risers.
Inspect the riser outlet for clogs/rust.

Volvo Penta Marine Engine Parts and Accessories Online Store - Volvo Penta 5.7GL-A gotta put it in just like that.

Thank you
Fortunately enough thermostat o-ring and gasket were bought before the boat left US.
As far as I know salt water only for selling the boat. the whole life was spent on a lake. I bought a spare manifold and raiser just in case though (why not 2 ? half the price ....half the coverage)
Manifold and raisers look good from the exterior comparing the ones reported on internet pictures before replacement: no sign of corrosion or leakage. as for clogs/rust in the outlet I see water flowing out without a problem. Is this good enough ? Do you think I still better pulled them out to check internally ?

the 10 minutes overheating might have damaged gaskets in cylinders or elsewere in the motor ?
Thank you
 

SeaLord

Seaman Apprentice
Joined
Oct 29, 2013
Messages
47
Re: 5.7 gla AFTER OVERHEATING CHECK LIST

dont forget the exhaust hoses from risers to your transom y-pipes. those also tend to not like to be heated up.

do a compression test as well.

not knowing which outdrive you have, a barrel is not a substitute for a proper set of muffs to get water up to the raw water pump for priming when the boat is out of water.

Thank you
Exhaust hoses...Do you mean part 20-25 in the following exploded view ?
https://www.marinepartseurope.com/en/volvo-penta-explodedview-7744290-25-6979.aspx

A compression test you say...How do I and what does it indicate test result ? On which parts CT may give me a hint they are not working appropriately ?

may a head gasket be blown (TH reading 230F for 5 mins)

The outdrive is a SX-M. Others on this site told me that, since the raw water pump is not under the water level, WP does not prime and this is where the lack of water for my cooling system came.
Waiting for the muffs yesterday I took a clog remover, extract the wooden rod. made a hole to fit the garden hose, covered the other side of the water intake with a pc of plastic. The raw water pump reacted well. I notice though that the garden hose is much smaller than the hose going to the raw water. Does it mean that at any given moment the garden hose is providing just half of the water needed by the raw water pump and the cooling system ?

Suppose that I hold a 5 gal tank on top of the boat connected to the year muffs through a hose. Would the pressure of the water coming from the tank be sufficient to properly feed the raw water pump ? I would like to circulate vinegar that way....
 
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Scott Danforth

Grumpy Vintage Moderator still playing with boats
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Re: 5.7 gla AFTER OVERHEATING CHECK LIST

items 12 and 22 are the reinforced rubber parts

to save yourself some money, measure them and buy a 4' stick of marine hose of the internet. they will be either 4" or 95mm. $86 each is steep for an 8" long piece. I think I paid $80 for a 4 foot long piece of marine exhaust hose a few years back.

regarding the garden hose. most spigots at pressurized, and a 1/2" hose will provide up to 20GPM of water. never run more than 1500 RPM on the hose

no, a 5 gallon bucket a few feet above the outdrive will not give you enough head pressure, or enough volume.

why are you running vinegar thru your motor?
 

SeaLord

Seaman Apprentice
Joined
Oct 29, 2013
Messages
47
Re: 5.7 gla AFTER OVERHEATING CHECK LIST

items 12 and 22 are the reinforced rubber parts

to save yourself some money, measure them and buy a 4' stick of marine hose of the internet. they will be either 4" or 95mm. $86 each is steep for an 8" long piece. I think I paid $80 for a 4 foot long piece of marine exhaust hose a few years back.

regarding the garden hose. most spigots at pressurized, and a 1/2" hose will provide up to 20GPM of water. never run more than 1500 RPM on the hose

no, a 5 gallon bucket a few feet above the outdrive will not give you enough head pressure, or enough volume.

why are you running vinegar thru your motor?
thank you
I understand that a part from rhe hoses you would not fear any other damage,
Vinegar is capable of dissolving salt since is acid. This is confirmed by some others that have done it on theirs removing substantially the remaining of salt. This I hope would improve the maintenance and extend some component life if done regularly, Does it sound right ?
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
Staff member
Joined
Jul 23, 2011
Messages
50,282
Re: 5.7 gla AFTER OVERHEATING CHECK LIST

salt-away works much better than vinegar, and it comes with an in-line hose injector
 
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