I have a 1993 240 (California Emissions) with 135,000 miles.
I just replaced the timing belt (Gates), front oil seals (Volvo), drive belts, water pump (HEMU), thermostat (Volvo 87 degree), and the temperature sending unit. (BTW, before I did all of this, I flushed the cooling system and the water flowed through freely.)

I also, put in new plugs, new flame trap, cleaned the throttle body and put in fresh Volvo coolant.

The car runs better than it has is a while.

However, the temperature climbs until it gets in the red and then stays there. I have felt the radiator hoses. The top hose is hot, the bottom is warm. I can squeeze the top hose and it causes the reservoir tank to burp. It doesn't seem like a lot of water is flowing through the hose to me.

I am stumped! can someone please help??

 

it coudl be a bad temp sensor

a engine thats actually in the red would smell VERY hot

any chance you put the thermostat in upside down? they don't work so good that way.

 

LOL, I wondered that myself and could not find anything on the proper placement of the thermostat. So, I installed it with the spring on the bottom and the point and jiggle valve on the top. Was this the correct way?

 

that sounds right, but I haven't done one in SO long that I don't honestly remember.

 

The temperature sensor you mentioned, is this the one that has the black plastic electrical plug on it? As I mentioned, I replaced the temperature sending unit (single wire). Prior to this work, several years ago, I installed IPDs temperature compensation board jumper. For the past several years, the gauge has never really given what I thought to be an accurate reading.

 

They only go in one direction on the 240. I just did one.

 

I dunno what color the plug is, but there are two temp sensors on the intake side of the engine block/head interface. one has 2 wires, and thats used by the ECU and ICU, the other has a single wire, and is used by the temp gauge in the dashboard. there's also an anti-knock sensor, which is flat,a nd has the single wire connector coming off the side

 

Did you set the heater control to full hot when you refilled?

 

Yes I did

 

UPDATE !
Today I tested the temperature gauge by placing the temperature sending unit wire on a ground point and the temperature gauge went all the way to the top. So we know the gauge is working.
Also, based on a recommendation from a local mechanic, I made sure the nuts that secure the gauge in the cluster were snug and they are.
Then, I decided to flush the system again. I flushed it and the water ran clear. While conducting the flush, I noticed that the air coming out of the heater vents was not really hot even though the gauge read hot and the top radiator hose was hot.
Any suggestions? Does this cause any light bulbs to go off?

 

sounds like maybe a stuck thermostat ?

 

I would be shocked if it was, the thermostat is a brand new Volvo 87 degree thermostat

 

Try revving the engine some while the heater is on

 

I would make sure that you really have an overheating problem. Get youself one of those infrared thermometers and check the hose coming out of the block to the radiator. If it is over 100C, that confirms your overheating. I don't trust the guage for determining the real temperature of the engine.

If you find that it is overheating, using the infrared thermometer, check the different parts of the radiator for hot/cool spots. It should generally be fairly uniform with an even temperature gradient from the inlet from the engine to the exit.

 

Update!!
The problem has been solved. As it turns out it was the temperature gauge sensor that I had recently purchased that was actually the wrong part. The place I purchased it from still listed as the accurate part but it is not. I went to the Volvo dealership and purchase the correct part and everything works perfectly.