1996 Volvo 850 Overheating Issue.

zyanmayfield · Post by **zyanmayfield** » 02 Jul 2014, 21:17

Hi Everyone!

I finally got around to fixing the temp sensor(ECT?) on my 1996 Volvo 850 Turbo to show temperature so it would not stall out. Now I have an issue with it overheating, It doesn't seem like it will ever get to into the Red area, but I don't want to run it for very long right below the red. For fear it will warp my heads. Here is what I know.

New thermostat and tested thermostat from my other working Volvo. So I crossed off thermostat.

The Fan kicks on so that doesn't seem to be an issue. Unless there is suppose to be different fan strengths?

I tried to flush the radiator with some crap cause I was desperate and lazy. Also ran a garden hose flowing into the bottom of radiator to top and from the top of radiator to the bottom both seemed to have a fairly decent flow, but don't know much about that. I was thinking that might test clogged radiator.

I don't seem to be losing any coolant and the oil level seems fine.

I drive for about 12 minutes before it starts to overheat then I turn on the heater full blast and that buy me another minute or so before it begins to go back up.

Seems to go down in temp when I take off and get going even though I am only going about 20.

The ECT had a problem in the connector so I just by passed it connecting the wire directly, doesn't seem like that could cause a problem but would just tiny bit of resistance cause it to act like it is higher?

Is there anyway it's like an oil not getting to the right places that is causing overheating?

Thanks for any help in advance! You guys have been great!

Thanks!
Zyan

Baptiste1106 · Post by **Baptiste1106** » 02 Jul 2014, 21:27

Purchase radiator pressure tester from harbor freight or local auto parts store to determine leak or air in system. To test the head gasket, purchase a block tester from napa auto parts. Instructions on how to test block is on youtube. Here the items you are looking for
Temp sensor
Overflow tank cracked
Thermostat
Radiator leaking
Coolant hoses leaking
And last but not least head gasket

zyanmayfield · Post by **zyanmayfield** » 02 Jul 2014, 23:08

Hi Baptiste,

I have crossed out a lot of those simply because I am not losing any noticeable amount of coolant. Correct me if I am wrong in doing so though.

As far as air in the system, is there some way I should be bleeding the coolant system? I thought this Volvo's air bubble just kinda made it's way back into the reservoir.

Thanks!

Post by **abscate** » 03 Jul 2014, 04:40

Definitely need to pressure test. These cars need substantial pressure in the cooling system to stop coolant from boiling.
Is coolant fresh?
Have you confirmed the overheat condition by measuring engine temp?
Did you replace the ECT or just solder the wires?

Post by **rspi** » 03 Jul 2014, 08:23

Eye-yi-ye, fill the system first thing in the morning before you start it, it will not fill properly when hot or warm. If you have a proper Volvo type thermostat with the bleeder pin in it, the system will fill 90%. Drive the car, if it tries to overheat within 30 minutes, verify this somehow, like a code reader that will report the coolant temp. If the car is really overheating with coolant in the system you likely have a bad water pump.

zyanmayfield · Post by **zyanmayfield** » 03 Jul 2014, 17:52

Thanks rspi I will give this a try. I should have a USB OBDII thing I can plug in and drive around with.

I'll let you know what I figure out with that!

Post by **rspi** » 04 Jul 2014, 08:01

zyanmayfield · Post by **zyanmayfield** » 15 Jul 2014, 22:38

Alright everyone. I know it's been a while and thanks for all your help!

I ran the computer on it while I drove it around. 220F Seemed normal operating temperature based on where the needle was at that temp. Then right below the line was about 257 which is where I run if I drive it for very long.

I just soldered the wires on the ECT so might try a new ECT. But the reading before the solder job and after remained the same. So maybe a bad ECT..

Here is a strange thing I can let it idle for a good 20 to 30 minutes without a problem I even rev it up a lot. But as soon as I starting driving the car around it will start to climb.

Again when I let it cool down and open the coolant it doesn't seem like I have lost any.

Any ideas? I'll try a different ECT Tomorrow.

Thanks!

Post by **rspi** » 16 Jul 2014, 03:21

Did you watch the video? The system is really simple. If the thermostat is good and you have no blockage in the system (super rare) the water pump is bad.

Post by **abscate** » 16 Jul 2014, 04:30

Revving it is not the same as loading it by driving it, I also suspect the water pump is bad.