Overheating Volvo 2001...

[EdEssery]

My Volvo 2001 is overheating under some circumstances. I can run it in gear in the pontoon berth and it seems fine. If I take her out and run the engine flat out, after about 20 minutes the overheat alarm sounds. If I back the revs off, it stops. If I don't push her so hard she will motor for about an hour at 2000-2500 revs before the overheat alarms; if I then back her off to idle for about five minutes the alarms stops and I can run her up to 2000 RPM again without an immediate repeat alarm.

The engine is new to me and has been installed by myself with a new thermostat and impeller at time of installation and using the injection elbow from my previous engine (it was easier to separate the elbow from the block than the exhaust hose from the elbow). The old engine was a very poor starter and had low compression but never had an overheat problem. The new one was surveyed before I bought it with no problems reported - it starts fine and runs sweetly with a lot more power (6.5 knots flat out versus 5.5 previously)

Any suggestions or information on similar symptoms welcome as I am planning to spend the weekend stripping the cooling system and would value advice.

Thanks,

Ed

 

[bendyone]

Depending on the age of the engine there was a mod that needed to be done to the water pipe which runs through the cylinder head. There is a hole in the pipe which directs water round the head and this needs to be opened out. We had 2 engines fitted to our cat and the mod was carried out by the volvo people in St Peter Ports under warrenty. This was in 1995 when the engines were new.
Your problem sounds the same as we had.

 

[markcozzy]

try not to run it flat out its like going down m1 @ 110 mph in a skoda try bleeding coolant and re fill at 50 % water 50% antifreez see how you go








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[KREW2]

Hi
I had a similar problem only it was a while ago when I didn't have time to sail, I had a power boat that only over heated when under load doing high revs,after a lot of trying and testing which costalot it was found to be a kinked intake hose.
good luck KW

 

[martinb]

I had a similar problem on my 2001 when I bought my boat, except the alarm didn't sound because someone had cut the wires. My problem was partial blockage of the exhaust elbow casting which was simple enough to dig out and has been fine since. If the problem is a cooling water problem, which it sounds like, I would have thought that it would be evident by lack of flow from the exhaust. After cleaning out my elbow the flow went from an intermittant spurt to a good healthy flow even on idle.

Martin

 

[Rustyknight]

Having had the same symptoms myself a few years ago, I'd agree with "bendyone" that it sounds like the water distribution pipe.

This pipe runs through the cooling jacket, taking water from the impellor pump directly to the exhaust elbow (which is why the flow of water seems ok running out of the exhaust.)

In the middle of this pipe (I think it has a bore of about 10mm) is one small hole of about 3mm. Its through this small hole that water enters the cooling jacket when the thermostat opens.

Much the same as a kettle, after a while this furs up...... restricting the cold water entering the cooling jacket even further.

It is possible (if I can do it, a monkey should be able to!) to drain down the engine and remove this pipe.... either to replace it, or clean it up and re-fit. After disconnecting the inlet and outlet ends of the pipe, it should tap out (from the back of the engine) quite easily.

There will be a few rubber washers that need renewing when you refit, so it might pay to be handy to a Volvo dealer when you do the job!

 

[boatmike]

Absolutely agree. When these engines first came out Volvo did this mod on a lot of them under warranty. Some escaped and I have personally done several for people since. If you need guidance on how to go about it visit any Volvo dealer. They used to have a data sheet telling you what to do but it's very simple and you should manage it yourself OK anyway.

 

[Nina Lucia]

I have same problem with my volvo 2001 would you mind teliling me how to drain engine and remove that pipe, please?
Best regards
Ivan
ivan.n@ntlworld.com

 

[Nina Lucia]

I have same problem with my volvo 2001 would you mind teliling me how to drain engine and remove that pipe, please?
Best regards
Ivan
ivan.n@ntlworld.com

 

[Ben_e_Toe]

See other forum post "volvo 9hp overheating" for help.