Highway Hesitation / Overheat

I have been driving my 87 244 (original owner) as my daily driver for 6 months or so now. A few weeks ago it started hesitating, on the interstate, in hot weather. Driving at night over the same distances I had no issue. So, I started to search the forums for a solution...

After following advice on multiple threads I have replaced:

Ignition coil, distributor cap, wires, and plugs
In tank fuel pump, main fuel pump, and filter
Both coolant temperature sensors
Oil separator box and flame trap

Here?s the rub. After replacing the CTS the temp gauge in the car reads dead center idling in the garage. However, as soon as I get moving on the road it shoots up just below the red. Shortly thereafter it starts to hesitate.

I just ordered a temp gun to check the actual temp but it makes sense to me that overheating would cause hesitation. Is it possible that it?s been overheating all along? With the old sensor the temp gauge showed right in the middle most of the time.

If it is in fact overheating, even at highway speeds, I fear a head gasket leak. If that?s the case I?ll probably just swap the B230F for a B230FT and never look back.

Dude, thermostat.

Been there and the more you drive like that the more you gonna hear sh1tty noises that will stay with the engine.
Trust me from average DIYer, red blocks can take beating, but if it actually overheating and you keep driving then be ready for head job or whole block job eventually.

You can also do bypass fake temp board in the cluster for more accurate reading instead of NORMAL and OHCRAP

Head gasket job shows some white smoke from tail pipe and engine oil would look like chocolate milkshake.

Yeah, today I'm planning on ordering a new water pump, radiator, and thermostat.

I had a gnarly head gasket leak on a Ford Escape a few years back. I'm not seeing any of the same symptoms except the hesitating and overheat. Hopefully the coolant system replacement will correct it.

Really my question is with the CTS. Would a failed CTS show normal temperature?

Do resistance check with multimeter and do the bypass fake temp board at least for test purposes.
It has 3 modes, Cold/Normal/HotToFuked

Just bypassed the faker. That was way easier than I expected. Should’ve done it sooner.

After starting, the temp started working it’s way up towards the red.

I hit the sensor with a multimeter and it read 77ish when set to 200 ohms. At that point it was still warm but cooling down. Not 100% what I’m looking for. I assume the warmer it goes the greater the resistance.

Hutch. said:

Not 100% what I’m looking for. I assume the warmer it goes the greater the resistance.

Click to expand...

I thought it was the opposite of that, but I can’t be sure.

An infrared thermometer is your friend here. When the gauge reads high, measure temp at the ‘freeze plug’ in the block, and at the thermostat housing.

http://cleanflametrap.com/ectCurve.jpg
https://volvoforums.com/forum/attac...-cold-start-problems-w-745turbo-ctslh2224.jpg
higher temperature, lower resistance. Do the measurement at the ecu connection. Make sure you replaced it with the correct sensor, lh22 and lh24 are different but look very similar.

Also remember there are 2 independent sensors, one feeds the cluster gauge and the other feeds the ECUs. You probably replaced the ECU one

If you have the original copper radiator, don?t get rid of it.

How often if ever have you changed your coolant. I just did a head gasket job where the old coolant corroded through the gasket and lesked to outside the block.

What ignition components are you running ? Bosch cap rotor, ngk or Bosch copper plugs and Oem wires only.

Stage 0 is crucial

Welcome to the boards.

esmth said:

http://cleanflametrap.com/ectCurve.jpg
https://volvoforums.com/forum/attac...-cold-start-problems-w-745turbo-ctslh2224.jpg
higher temperature, lower resistance. Do the measurement at the ecu connection. Make sure you replaced it with the correct sensor, lh22 and lh24 are different but look very similar.

Also remember there are 2 independent sensors, one feeds the cluster gauge and the other feeds the ECUs. You probably replaced the ECU one

Click to expand...

I changed both sensors but, I'm not sure about lh22 or 24. I'll have to go back and double check.

It’s lh 2.2

Jack said:

If you have the original copper radiator, don?t get rid of it.

How often if even have you changed your coolant. I just did a head gasket job where the old coolant corroded through the gasket and leaned to outside the block.

What ignition components are you running ? Bosch cap rotor, ngk or Bosch copper plugs and Oem wires only.

Stage 0 is crucial

Welcome to the boards.

Click to expand...

I have been pretty diligent changing the fluids... over the last few years anyway. Right now I've got a Bosch cap, NGK platinum plugs and whatever wires they had at Autozone. It seemed to be running okay with those, didn't get worse anyway. Could non-oem wires and plugs cause an overheat?

Ugh get rid of platinum plugs and ****ty auto zone wiring. It is terrible

It will cause bad spark making it run ****ty. May or may not be overheating

Usually your car will overheat at idle, if at highway it’s probably clogged radiator or partially open t stats ... but you have to fix your temp board first

Update:

After having a few beers and considering my situation, I had an epiphany. The temperature was rising so rapidly after engine start that it was almost as if there were no coolant at all. I decided to take the BRAND NEW O'reilley's brand thermostat out and run without one, just to see. Temp held solid at 1/4 above the center line, which I understand is not unusual after bypassing the faker board. Tomorrow I should be receiving the infrared gun but, I can't help but assume it is nothing more than a faulty thermostat.

This still doesn't answer the original questions though.

Can a faulty CTS indicate normal temperature?

Was the hesitation a symptom of a chronically overheating car?

I guess time will tell.

LH 2.2 engine coolant temp sensor should be about 294 ohms at operating temp. Looks like you have an overheating problem. But I wouldn't rule out a bad water pump as the cause. The thermostat could also be a cause.

As my first post states, I still strongly consider the thermostat problem. I also run few degrees lower thermostat with a drilled minor hole at the top for air.

The correct thermostat will have the jiggle valve. You need a 87*C Wahler/Vernet thermostat. Price of this thermostat is less than $12. Carquest/Advance Auto is reboxed Wahler/Vernet.

smeha said:

As my first post states, I still strongly consider the thermostat problem. I also run few degrees lower thermostat with a drilled minor hole at the top for air.

Click to expand...

Yes, it's an easy maintenance item that is worth replacing in either case.
The only reason I posted the link about Coolant Temp Sensor, was for clarification.

I ordered a thermostat off of FCP. Without a thermostat it’s holding steady around 65C so, I think I’ve got the overheat licked.

After all this it looks like there were compounding issues. The malfunctioning temp indicator and CTS masked the overheat, which was causing hesitation/stalling. The overheat was caused by a faulty thermostat.

On to the next