fitted new thermostat worried

jpliddy · #1 09-28-2016, 01:30 PM

hi all i have just fitted a new volvo genuine thermostat and replaced coolant with the same volvo genuine coolant just done a 4 mile run the top radiator pipe was very hot . the bottom pipe ago the radiator from the thermostat was still cold/cool
the coolant reservoir was still cold so is all ok with my change over as i have no working temperature gauge just a bit worried please advise me if all is ok before i drive car again car is a d24 tic 940 1995
regards jim

anders · #2 09-28-2016, 03:05 PM

Did you bleed the air out of the system?

jpliddy · #3 09-28-2016, 10:54 PM

yes i bled the system according to volvo green book undid cold stat hose ran engine and kept filling up till reservoir was full i may just have been to concerned but i take it coolant in reservoir never gets warm as coolant is not pump there its just a top up vessel

jpliddy · #4 09-29-2016, 05:57 AM

hi all i am now thinking all is ok with my new thermostat as engine seems to be running fine

v8volvo · #5 09-29-2016, 01:11 PM

You need to fix the temp gauge before starting the engine again.

Let us know how we can help.

jpliddy · #6 10-03-2016, 01:04 PM

hi the temperature gauge/ fuel gauge has been a problem for me for ages i even purchased a second hand dash exact same but that does the same thing fault somewhere,
i cleaned both circuit boards . swopped voltage stabiliser still no luck perhaps they are both faulty gets you down after a while

v8volvo · #7 10-03-2016, 03:21 PM

Some of the later year 700 and 900 cars have trouble with the instrument clusters, it is possible they are both faulty.

Does anything else in the instrument cluster not work? Warning lights, fuel gauge, speedometer etc all work fine, just the temp gauge is broken? Or are there other problems in the cluster too?

Have you checked circuit continuity between the cluster connector and the wire terminal at the gauge sender near #1 glow plug on the engine?

If no continuity there, then check for continuity between the cluster connector and the large multi-pin engine harness connector near the left hand shock tower under the hood, and also continuity between that harness connector and the sender terminal. An open in the circuit would cause the gauge to be inop and this is how you would find it. Wherever there is no continuity is where you will need to start tracing for the fault. Could be in a wire on the engine or body side, or poor contact at a harness connector, either that one under the hood or the large multi-connector under the dash inside the car.

Another quick way to test this is to unplug the sender on the engine and ground the wire going to it. Gauge should sweep to full hot with the terminal grounded. If not, there's a circuit problem, and you'll need to diagnose it as described above.

If the gauge does read full hot with that wire grounded, then you have a bad temperature sender, easily replaced.

Engine wiring problems are not as common on the later models like yours as they are on the '80s cars. I think you'll find it's a cluster or sender issue on yours. You will find it easy to fix once you dig into it. The system is not complex and all the circuits you need to check are easy to access.

Worst case if you simply cannot find the issue, consider adding an aftermarket temperature gauge. Running with no temperature gauge is asking for a catastrophic failure that you can avoid by having temperature information. Lots of options for getting it.

We're standing ready to help here. The above steps should be a good starting point. Any questions after completing all of them, just ask.

ngoma · #8 10-04-2016, 02:17 PM

Quote:

Originally Posted by v8volvo

Another quick way to test this is to unplug the sender on the engine and ground the wire going to it. Gauge should sweep to full hot with the terminal grounded. If not, there's a circuit problem, and you'll need to diagnose it as described above.

If the gauge does read full hot with that wire grounded, then you have a bad temperature sender, easily replaced.

There you have a quick and easy test; no reason to remain discouraged.

In addition to a working temp gauge, I think these cars need a low coolant sensor/alarm, which I believe you car has.

jpliddy · #9 10-07-2016, 09:47 AM

hi all
thanks for your valued input on my faulty temperature and fuel gauge .
there are no problems with the speedo /rev counter and clock .now i did manage to blow the clock fuse and only found the fault with the door open illumination lights being off so i changed the fuse and all was ok . i did not disconnect battery when removing dash which i have done a few times now .
i have seen on a electrical drawing there is a link at the very bottom of the circuit board but I'm unlucky if both circuit boards i have now are faulty as both come up showing the same fault
temperature gauge goes straight to 11 o'clock from cold and stays there and fuel gauge goes straight to full and stays there always so i need a man with the multi meter who knows what to look for .
thanks again all of you

v8volvo · #10 10-10-2016, 08:02 PM

Sounds like you might have two faulty instrument clusters. The clusters on the 1991+ 700 and 900 series are chronically troublesome at least on US cars here, can be difficult to find a good one. Getting two bad clusters in a row would not be too unlikely.

It sounds like you are saying the speedometer and tach work but the fuel and temperature gauges are both faulty? That will help diagnose the problem if that is true.

Did you try the test of disconnecting the temperature gauge sender wire (in front of #1 glow plug on the side of the cylinder head), touching it to ground, and seeing if the gauge reacts?