Need someone to point me in the right direction with an Penta AQ170

A10ha10ha7

Recruit
Joined
Sep 3, 2018
Messages
1
Good day, I just bought a 72 Glastron v 187 Tri Hull open bow with an Volvo Penta AQ170 inboard on an AQ270 drive.

when I got the boat the freeze plug on the cylinder head was popped. Little bit of water in the engine oil.
i m planing to replace the freeze plug to test if the engine has a good block.

i couldn’t find a workshop manual for the AQ170 so I got the Volvo 1969 164 b30 workshop manual instead. But seems like the water cooling system is totally different.

ive been reading a lot of tip and knowledge people share on the AQ170 seems like everyone is pointing to a weak cooling system.

I don’t understand how the cooling system works on my AQ 170. Do the raw water pump pumps water to the recirculating pump and the engine uses raw water pump to cool the block? Or does it use antifreeze to cool the block. I don’t have a strainer on my, and no antifreeze overflow no heat exchanger that holds antifreeze

i was thinking to myself since AQ170 is an old rare engine if my block is good after replacing the freeze plug I m thinking mabe I should use the car side of thing for cooling by using air cooled radiator and a fan and antifreeze make it into a close loop for the block. I saw Ipdusa sells some flexible lower and upper radiator hose and a 160f degrees thermostat for the engine.it seems very doable it must extend the life of the engine by not letting sea water in the block I think.

and useing the sea/raw water pump to cool only the exhaust. But I can’t find any info on the AQ170. Has anyone had done this before can give me some pointer to which cooling pipe to block off to go close loop antifreeze radiator and fan setup.
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
Staff member
Joined
Jul 23, 2011
Messages
47,297
welcome aboard

no way to get enough air flow with a radiator. not to mention you now have hot surfaces in the bilge

fix it right

your cooling system depends on if you have a heat exchanger or not

with a heat exchanger, the raw water pump provides cooling water to the heat exchanger and exhaust and the circulating pump circulates the glycol around in the heat exchanger, block and heads

in a raw water cooled system - raw water pump provides water to the block, exhaust, etc. circulating pump just circulates water within the system. water exits via the exhaust.

as for if your block is ok because a core plug was pushed out. probably not. the core plugs are intended to get casting sand out of the casting core at the foundry
only way to test is to pressure test the blocks water jacket. however be prepared for the worst.

also, on your 47 year old boat, did you check for rot in the stringers and transom. the motor may be the least of your issues.
 

kenny nunez

Captain
Joined
Jun 20, 2017
Messages
3,056
If it turns out that the hull is in good condition then the good news is that the drive on your boat is rated for a V8 engine.
There are a lot of used parts that can be found to up date the boat. Volvo engine parts are really $$$$$$$. The way the engine is mounted in the transom it is easy to get an adapter for a later GM, Ford or Mopar.
 

dennis461

Chief Petty Officer
Joined
Aug 11, 2011
Messages
516
post some pictures of your engine bay showing cooling hoses. And a pic of anything on front of engine, so we can figure out how to help you. If you do rebuild/modify the cooling system it would be with a water to water heat exchanger, not an air to water heat exchanger(radiator).
 
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