Engine Temperature

[Scrimshaw4]

I have a Westerbeke 82 B 4 diesel auxiliary engine that won't come up to temperature. Background: heat exchanger has been cleaned and pressure tested, engine coolant has been drained completely, flushed, rinsed and replaced with new 50/50 mix, thermostat has been replaced (removed, temperature checked and reinstalled).
With engine running under load, 2200 RPM, for an hour: Coolant checked for cross contamination, blower motor off so no cold air into engine compartment (outside temp is 58F). Max heat gun reading at thermostat is 163. 180F Thermostat not opening.
Prior to flushing coolant and replacing the thermostat it ran at 180F.

Any ideas on why this might be happening would be appreciated.

[Wotname]

Heat gun readings are rarely accurate but very good for giving trends and comparisons.

Presumably you don't have any other temperature gauge fitted so the previous reading were taken with the heat gun. If so, maybe the engine was running hotter than you realised before you carried out the cleaning and flushing etc.

I would be looking for another way of checking the temperature at this stage.

[dkenny64]

any chance the thermostat is sticking open?
chance the thermostat is not a 180 but a 160?


-dkenny64
I've had a piece of dirt stop mine from opening...

[Don C L]

Yeah I was thinking too that a piece of gunk in there preventing its closure.

[Captndave1]

Take the thermostat out and look at it, there will be a mark showing the opening temperature, if still in question put the thermostat in a pot with a cooking thermometer and watch the temperature when it opens.

[Scrimshaw4]

The issue is that the engine will not get up to the 180F operating temperature and open the thermostat. When run without the thermostat, raw water temp to the heat exchanger at 58F, I can put my hand on the exhaust ports. The heat gun has been checked and is within 5F accuracy. The temp is further verified by the engine's temperature gage.

[kchace]

You say that prior to replacing the coolant and thermostat it DID heat up to 180. So if you did nothing else, it is the thermostat.


Ken

[Don C L]

Originally Posted by Scrimshaw4

The issue is that the engine will not get up to the 180F operating temperature and open the thermostat. When run without the thermostat, raw water temp to the heat exchanger at 58F, I can put my hand on the exhaust ports. The heat gun has been checked and is within 5F accuracy. The temp is further verified by the engine's temperature gage.

Right, so the thermostat may be jammed open disallowing it to warm up completely.

[Joli]

When were the nozzles last changed? You may not have combustion in all your cylinders?

[jamhass]

Originally Posted by Don C L

Right, so the thermostat may be jammed open disallowing it to warm up completely.

This.