Engine temp?

[chad1966]

Is this a normal range for the temp to be in?
https://www.dropbox.com/s/3yb7ij7t89...2014.36.03.jpg

[Vomaz]

Yes, for me comes the guage up to that area if i drive hard and have turn up the boost..

but if i cruise then it is a bit lower then middle

[anders]

I think that is in the high range of normal. I have never seen my 240 that high, but it's also running colder then normal for some reason. You can always add a second temp gauge if your worried.

[745 TurboGreasel]

The Volvo temp gauge is a steaming pile with a dead spot somewhere near the middle from 170--210+
A google search of Volvo 240 temp compensator bypass may be informative.

The gauge is tested by hooking it to a 68 ohm resistor between the sensor wire and ground, the gauge should move up to the 3/4 position on the scale.

Pull the single wire off the single wire sensor at the cylinder head and touch/jumper that to ground. The gauge should move to the top of the gauge.

If not the gauge is faulty.

[v8volvo]

The earlier 240's (like yours) didn't have the compensated temp gauge with the dead zone in the middle so they move around much more actively, reflecting actual engine temp (which the later ones and the 700 series gauges do not). All the 240 diesels had non-compensated gauges and all the ones I have driven have moved around like that, with a stock t-stat sitting at 9:00 in normal driving and climbing to about 10:00 when pulling a hill. One of the unfortunate flaws in the D24/T cooling system is that the temp gauge sender is located very far from the thermostat, and is up in the head right next to a prechamber so the temperature of the fluid and head material surrounding it can fluctuate relatively greatly even while the temp of the coolant down near the t-stat remains comparatively constant. Thus the gauge can move around quite a bit during normal use in the absence of the compensation used on the later models.

so IOW what you are observing is normal for a diesel 240, however disconcerting it may be, and doesn't indicate a problem per se -- just don't let it get much higher than that.

I have lately begun to lean towards the conclusion that an 80C thermostat is a better idea for these motors than the stock 87C, since I think the coolant up in the head is often quite a bit hotter than what is down near the t-stat, and due to the layout of the cooling system, the coolant that flows past the t-stat may not be the hottest coolant in the motor, and that differential may even in fact be variable based on outside factors like heater operation etc which ideally should not influence the thermostat's activity. With a thermostat one notch cooler the temp seems to stay considerably more stable, which probably is therapeutic for the headgasket, a known fragile part of these engines....