AQ290A cooling system

[diesel1960]

Getting ready AQ290a engine in my CC 251 Catalina project boat,anybody still using this engine?
Need some pics or schematics for routing cooling system houses including oil cooler etc.

 

[Scott Danforth]

What issues are you experiencing?

Very simple engine. Small Block chevy, crank driven raw water pump.

Main issue with volvos is the inlet casting needs replacing annually. Even dipping in epoxy doesn't help

 

[wrench 3]

If you go to http://boatinfo.no/lib/volvo/manuals/aq200_260.html#/6 It doesn't have a cooling system schematic but it has some good photographs of the engine with all the hoses on it at the front of the book.

 

[diesel1960]

3 years ago stripped entire boat for rebuild, lost all files with picks I took, now putting everything together, need to figure out housing ,making new wire harness and so on... Which inlets casting are not good?

 

[diesel1960]

No Title

recent engine photo

 

[diesel1960]

Also found out that existing thermostat in this engine AQ290(GM 350 CID)is 140* but recommended for those engines is 160* ,any ideas why previous owner used 140?
Thank you.

 

[wrench 3]

Mercruiser used 140* thermostats in their older engines. Someone probably just thought it was the right thing to do.

 

[diesel1960]

Thank you wrench 3

 

[Scott Danforth]

You get more wear with the 140. Volvo recommended 160, Merc recommended 143

 

[jeffnick]

This may help a little...
http://72land-n-sea.blogspot.com/2014/10/engine-heat-for-hot-water.html

 

[diesel1960]

So it will open earlier but when fully warm-up should run at same engine temp whether 143* or 160*
Using in summer freshwater only.

 

[wrench 3]

So it will open earlier but when fully warm-up should run at same engine temp whether 143* or 160*
Using in summer freshwater only.

If I understand your question correctly the answer is no. The number on the thermostat is were the engine should should operate at.

 

[diesel1960]

Regardless of opening temperature ,most open cooling system engines run around 180*F anyway ?
The engine will warm up faster with 160* ?

 

[wrench 3]

Regardless of opening temperature ,most open cooling system engines run around 180*F anyway ?
The engine will warm up faster with 160* ?

I don't know why you'd say that. Mine is a 454 Magnum and it runs right around 140. Around here a boat with the thermostat stuck open or removed will usually only get to about 100*. And I don't think our lake temperatures are any colder than yours.
Regardless a warmer running engine will burn fuel more efficiently and get less contaminants in the oil.

 

[diesel1960]

Make sense ,thank you wrench 3.
Will upgrade for 160*

 

[jeffnick]

I believe there's a difference in marine thermostats - salt vs fresh?

 

[wrench 3]

I've never seen a listing for different stats.