Volvo Penta 5.7 GI PMDA - Fresh Water Cooling Question - HELP ASAP - Wanna Go Fishing

Status
Not open for further replies.

cc190cc

Petty Officer 2nd Class
Joined
Jan 17, 2010
Messages
198
Greetings,

I purchased this boat last year with a blown engine, the PO overheated it and wiped it out. I replaced the engine over the winter and got it running well. I then forgot to drain water from manifolds and exchanger and cracked them, no damage was done to the engine.

I ordered replacement manfiolds and bought another heat exchanger from a local. After some research i have found that the mercruiser exchagner i bought has an extra port on it for a heater, dont know which port is actually for the heater but figure ill just block it off.

The old heat exchanger was installed incorrectly, it was a san juan setup with the radiator cap on the thermostat kneck. The exchanger itself was located above the radiator cap, if i opened the cap, all coolant would come out. I have my suspicions that this was causing an air bubble in system and likely why old engine failed after 5 years. When i filled the system up after motor replacement, i had to remove one coolant hose from the exchanger to add coolant.

I considered ordering an identical replacemetn exchanger and mounting below the engine where it belongs, though there is not enough room for it.

The replacemetn I purchased is a mercruiser unit with the radiator cap built in, I know the cap needs to be the highest point in the system. The exchanger has a total of five ports on it.

Will I have any problem using this system exchanger with me Volvo penta exhaust manifolds. There are a lot of hoses and im starting to get confused, and im starting to get anxious because i should be fishing. If i had a few extra $$ i would pay someone to finish it. Im very mechanically inclined, just need a little guidance on the plumbing.

Does anyone have a diagram or something, my old manifolds only had 1 hose going to each, some picutres i have found online have multiple lines going to the manifolds.

I can post pics if it would help, really hoping for sea trial this weekend. It ran great when I started it prior to the manifold and exchanger freeze up.

I can post tons of pics if it would help, just tell me what you need to see.

Chad
 

cc190cc

Petty Officer 2nd Class
Joined
Jan 17, 2010
Messages
198
Re: Volvo Penta 5.7 GI PMDA - Fresh Water Cooling Question - HELP ASAP - Wanna Go Fis

Oh come on guys, I know someone can point me in right direction. Should I post this inthe Mercruiser section maybe?

Chad
 

Don S

Honorary Moderator Emeritus
Joined
Aug 31, 2004
Messages
62,321
Re: Volvo Penta 5.7 GI PMDA - Fresh Water Cooling Question - HELP ASAP - Wanna Go Fis

Without knowing what port in your new heat exchanger goes to what, it's impossible to answer your question. You have something that is not designed for your system, and trying to use it. Volvo and Mercruiser do not use the same type cooling systems, and the thermostat housings are different and there are just a lot of unknowns that looking at pictures won't answer.

PS Heater outlets do not come off of the heat exchanger. They come off the engine.
 

cc190cc

Petty Officer 2nd Class
Joined
Jan 17, 2010
Messages
198
Re: Volvo Penta 5.7 GI PMDA - Fresh Water Cooling Question - HELP ASAP - Wanna Go Fis

Greetings,

Thanks for your feedback. What is the difference between a volvo 5.7 and mercruiser 5.7....and chevy 5.7 ..the only difference is the name on the manifolds. I was going to change the water kneck over to the standard 350 water kneck. Raw water pumps are the same bteween mercruiser and volvo, manifolds have the same water lines as mercruiser... I have posted this int eh mercruiser forum also and those guys are saying it will work fine?

How are the cooling systems different and what are the unknowns. The exchanger I got came from a 350 and has 5 ports on it. Thanks for all the help.

Chad
 

Don S

Honorary Moderator Emeritus
Joined
Aug 31, 2004
Messages
62,321
Re: Volvo Penta 5.7 GI PMDA - Fresh Water Cooling Question - HELP ASAP - Wanna Go Fis

I closed your thread in the Merc forum, it's frowned on here at iboats to post a question in more than one forum.

First of all, the cooling systems between Merc and Volvo are different. The raw water pumps are NOT the same, on Volvo and Merc, the circulation pump is, but not the raw water pump.
Merc sometimes uses heat exchangers for cooling the manifolds as well as the engine with antifreeze, Volvo doesn't. This makes it hard to say what your heat exchanger is actually setup for.
You might post some pictures of your heat exchanger and it's ports, along with your engine and the thermostat housing and see if we can figure out what you have,
 

cc190cc

Petty Officer 2nd Class
Joined
Jan 17, 2010
Messages
198
Re: Volvo Penta 5.7 GI PMDA - Fresh Water Cooling Question - HELP ASAP - Wanna Go Fis

The only reason i double posted is because nobody was responding here, and the mercruiser section has more followers. Kinda sucks you deleted it, its sorta not a volvo or mercruiser question and someone other than you was responding there. I would have preffered you closed the one with no response which is this one.

Either way, Ill post pics later, i have talked to a few other people and they all say it will work no problem. I will obviously have to change the water kneck but thats easy, not sure what the difference between the raw water pumps is, can you explain further. I have a merc pump and volvo pump, they look the same, impellers similiar size.

I appreciate the help.

Chad
 

Don S

Honorary Moderator Emeritus
Joined
Aug 31, 2004
Messages
62,321
Re: Volvo Penta 5.7 GI PMDA - Fresh Water Cooling Question - HELP ASAP - Wanna Go Fis

The only reason i double posted is because nobody was responding here, and the mercruiser section has more followers. Kinda sucks you deleted it, its sorta not a volvo or mercruiser question and someone other than you was responding there. I would have preffered you closed the one with no response which is this one.

No problem, other thread opened, this one closed. PS, only 1 person posted there too.
 
Status
Not open for further replies.
Top