Volvo 4cyl - overheated apparently

[Peter1950]

1983 Bayliner 19" Bowrider with Volvo AQ 125 engine and 270 outdrive. Ran fine. During top speed the temp gauge said just off center towards hot. At launch ramp upon leaving I opened the bilge rain but antirfreeze came out! Gallon or more I'd guess. I see small pools of green around both sides of the engine but nothing especially obvious whats leaking. Runs fine. Suspecting maybe the 'Rad' cap since the fluid is both sides of the engine. Where is the T-stat and how much antrifeeze should go in this? Is there a burping required?
What psi should the cap be?
Peter

 

[kamby]

Re: Volvo 4cyl - overheated apparently

My cap is 4lbs. The t-stat should be right behind the antifreeze cap theres a bend pipe between the block and tank.
These engines run hot, between 180-190. i dont think the thermostat starts opening until 180 - 185. And there a cold blooded engine mine doesnt like to go above idle until the engine reaches 180 and then u can hit it or it will stall.

 

[Peter1950]

Re: Volvo 4cyl - overheated apparently

4lb cap? I was thinking mine was 16 but need to check. Where does the fluid go if the cap opens?

 

[kamby]

Re: Volvo 4cyl - overheated apparently

I dont know. When i look inside the spot where i add the antifreeze theres two holes, my guess is that is either goes into the bilge (never seen antifreeze) or it gets pushed into the sea water system and out the drive. I thought that it was too low of a PSI cap, but its what recomended by Volvo.

Volov PN 829205

You can get low psi caps at napa, mine has a stants on it. Too high of a PSI and you risk blowing things, the front of the tank is screwed on with with a big square gasket, dont want that blowing out. Make sure to pick yourself up a cheap antifreeze tester to check or freeze/boiling point

 

[JAL51974]

Re: Volvo 4cyl - overheated apparently

Not leaking around the heat exchanger strainer housing or where the heat exchanger connects with the fresh water tank is it? those are the obvious places to investigate on the front of the engine. On the rear of the engine just behind the copper pipe on the manifold I think there is a petcock type of unit to drain the antifreeze from the engine manifold. that could be leaking too.

These engines do run hot as others mentioned already, but I would not want to run mine beyond 190 degrees...too many bad things can happen.

Joe

 

[Peter1950]

Re: Volvo 4cyl - overheated apparently

Just not sure where its leaking. Didn't see anything apparent except it was green on both sides of the each which has me thinking its something up high. I first saw coolant around the strainer plastic area, then on the other side low down at the bottom of the block where the oil pan attaches. I'd expect one or the other. I checked for water in the bildge about half way through the outing and it was only less than a quart of fresh water (another issue to sort some time). But after that we ran some speed blasts then came in.
How do you know Volvo recommends 4psi? I mean where is it stated? Where do I buy parts? Same basic engine as an 83 Volvo 240 or something sedan isn't it? I know the starter is.
Peter

 

[kamby]

Re: Volvo 4cyl - overheated apparently

You can get a new cap here at iboats.

http://www.volvopentastore.com/HEAT...*****.895177569--store_id.366--view_id.325859

Yeah same engine as a 83 volvo 242 or something, B21 engine. From what i was told dont run the higher psi cap, cars have sealed radiators that dont have gaskets and are bigger. Boat just has the expansion tank and heat exhanger with gaskets. Im surprised the service manual i have doesnt show the psi, does say the thermostat doesnt start opening till 180 and is fully open at 198

 

[Peter1950]

Re: Volvo 4cyl - overheated apparently

I've looked at various manuals and so forth and can't find anything that shows the PSI of the cap. Still not sure where the thermostat is. There are two water pumps, one fresh and one sea water, but where is the fresh water pump?

My first boat, but I'm pretty mechanically and electrically competent thank goodness as I could see this being an expensive hobby! I'm just still learning the system and I think the simple 4cyl with decent access is a good start.

Peter

 

[kamby]

Re: Volvo 4cyl - overheated apparently

Fresh water pump should be right below the expansion tank, i runs of the altenator belt i belive. The thermostat should be right behind the expansion tank where the pipe goes from the engine back into the expansion tank.

 

[tbear1964]

Re: Volvo 4cyl - overheated apparently

Look for the lifting eye next to (to the right) of the heat exchanger expansion tank. That is the thermostat housing. It is probably not the source of the leak.

You will need to refill the engine block with 50/50 antifreeze and run it on muffs. No use guessing what blew. If it was only a gallon, it could be just a seal or a drain plug came loose.

If you want your engine to run cooler, take out the thermostat, and wear it as an earring. Mine runs 165-180 without it. PO took it out years ago, (he had it 7 years, I've had it 3) after an overheat blew the head gasket. No temp-related problems since. It has worked for me, and I have no plans on "fixin' what ain't broke". Only overheats have been from a clogged heat exchanger. (I boat in shallow, silty lakes)

http://www.dougrussell.com/ is a good source for older VP parts, but they have a $30 minimum order. I usually add some outdrive o rings or a gasket or two to fill out a short order.

 

[Viking...]

Re: Volvo 4cyl - overheated apparently

The cap is definitely low psi on my unit as well, so 4 psi sounds about right (same engine and drive). Stant has 7 p.s.i. models at the local Canadian Tire, which would be a reasonable replacement I think.

If the cap released some coolant, most will evaporate from the hot engine and leave some green evidence in various nooks and crannies. Very little will actually make it to the transom area.

Check the impeller. Seems that for our particular engine it's critical that this item is changed regularly, and in new/excellent condition.

Check the heat exchanger element and clean it while you've got it out.

I'm not a fan of running an engine without a thermostat, since the engine is designed to operate within a specific temperature range for many reasons.
Just my opinion, not dissing anyone else.

It's my feeling that because our particular engine is designed to run at a higher temp, we don't have as much leeway when it comes to worn down or dirty cooling parts.

Hope that helps, good luck mate.