Hi!

1990 Volvo 240 DL 5 speed wagon.

I just had the cluster replaced - well, a couple of weeks ago, and have not put on many miles at all - a couple of miles to town and back 3 or 4 times a week. The gauges seemed fine although the temperature gauge needed seemed to go up some - not a lot, just more than the other one - which was fine.

Then one day it just went to the red zone after I went about a half a mile or so. And that what it is still doing. One of my sons checked it out thought it just might be the thermostat. So we replaced it - added water and coolant and started her up and let it run and the temperature gauge needle went back up to the red zone.

So we're thinking the cluster wiring from the cluster recently installed? The sensor? There is NO radiator cap (the first car I have had without one) to add water/coolant so we had just filled up the coolant tank.

We let it run for a while with the needle in the red zone and it did not seem to be getting hot, so it looks like it was not the thermostat.

Any ideas?

I am going to call the guy on Monday who put in the cluster - and has done everything on the Volvo since I have had it since August 2013.

Until then I am not sure if I ought to drive it - even a short distance - like a mile or two which is what I have been doing since he put in the new cluster.

 

real question is, how hot is hte engine when its goin gup to the red zone. an overheating engine is obvious, and smells it...

and yes, you fill these coolant systems via the overflow bottle.

 

With the car running and warm feel the top large radiator hose to see if it is hot. Also do we assume that after you shut it down no water comes out of the overflow hose. And yes you have a radiator cap as it is in the top of the pressure tank as it is not an overflow tank.

 

Hi Pierce,

not hot at all. today after I started it up the needle started moving up - which has happened a couple of times.

but mostly it's all the way down and I can drive maybe a half a mile or maybe a mile and it starts going up.

 

ok. I will try it. I think he did though after I started it up.

it was right after we replaced the thermostat and added coolant/water that I started it up and the needle started going up right away.

And no there is no water coming out anywhere.

 

and drove exactly .8 of a mile. the needle started going up as soon as
I started it up.

by the time I parked it was close to the red zone.

the car parked for about 20 minutes and I started it up and the needle started going up right away like usual.

by the time I got back - the same distance - it was already in the red zone.

I felt the top hose and it was barely warm at all.

About the cluster, the guy replaced the one I had and there was still a starting problem as before so he took it out put it back in
and said that something was not hooked up right so he fixed it put it back in.

So I am wondering if it's the cluster - he put the first one in on 2/18 and did it again on 3/21. Could it be that the temperature gauge
in the cluster is off?

 

if that hose is barely warm, that sounds like the thermostat isn't opening up, and water isn't going through the radiator, and yes, this would lead to overheating.

did the engine 'smell' hotter than a normal warmed up engine? its pretty obvious

 

is it possible you installed the thermostat upside down or something?

 

No, it did not.

 

It is possible but not likely. Is it even possible to do that?

My son has been working on cars for quite a while and done lots of different repairs.

What about the sensor?

 

the temp gauge sensor is a separate sensor than the CTS sensor that the ECU and ICU uses for engine management.

on the instrument panel there's a 'temp compensator' circuit which is designed to keep the needle dead center if the temp is anywhere in normal range. if this circuit has malfunctioned, thbat could drive the needle all the way up.

 

well, it has been established that it is not overheating. probably did not need the thermostat replaced but now I got a new one in there.

he found the sensor for the coolant and took it off and cleaned it off lightly and plugged it back in.

he drove the car up to auto zone cuz they can check the sensor - but they could not cuz the volvo is too old. but what did happen is that the needle did not go to red - maybe about 2/3 up to where the red zone starts.
and the radiator hose on top was nice and hot when he got back.

so it's not overheating. he actually never thought it was cuz the classic signs were not there.

here is a vid that was cool to find. my exact model volvo and the sensor:

1990 Volvo 240 Coolant Temp Sensor IAT Replacement - YouTube

so we took it up to my mechanic who has the stuff to test it for sure.
and I guess take out the cluster again and check for what you mentioned above - ?

do you have a link to the wiring diagram for the cluster for this model volvo?

 

actually, here it is:

http://www.ohio.edu/people/ridgely/volvo_docs/documents/volvo_240__1990.pdf

so in this diagram - the last page is the cluster - could you please point out where exactly is the "temperature compensator" circuit.

I don't know what "CTS sensor that the ECU and ICU uses for engine management" are - what those letters represent - ?

 

that drawing doesn't show the temp compensator circuit as its integrated into the instrument panel. it is in the circuit between connector 31/2 and the actual gauge

CTS is the coolant temp sensor, the ECU is the fuel injection control unit, and the ICU is the ignition (spark) control unit.

CTS is also called ECT (Engine Coolant Temp). here's a FAQ on the engine sensors...
http://www.swedishbricks.net/700900F...eSensors1.html

you'd test these with an ohm meter and a glass of hot water.

 

OK thanks Pierce, I will check out the link