Volvo ECR305CL Overheating

hey guys,
Have a Volvo trackhoe overheating issue. I went to the unit and ran it to diagnose the issue. Running the machine hard it takes about 15 minutes for the temp to slowly sneak up to overheat temperatures. Once the load is removed the engine cools quickly back to normal. It was around 0 C/32 F ambient outside when testing. With a laser temp gun I shot temperatures as follows. Back of head 220 F. Thermostat housing 210 F. Top rad hose at rad 200 F. Rad hose coming back to water pump 185-188 F.
I spent a good 45 minutes blowing out radiators. Got a lot of dust out but it made no difference.
Unit has a hydraulic fan. On the dash the fan speed does not register. Shows 0 rpm. The fan is spinning when it says this, but not very fast.
I feel the fan is not spinning fast enough and it is an air flow through the rad issue. The temperatures I shot indicate inadeqaute cooling through the radiator. Coolant flow seems good. Thermostat clearly opening and I don’t believe is a problem.
Any ideas or info on this fan circuit would be a huge help.
Is it a variable rate fan?
Or Fixed displacement and needs a pump or motor? (Change quite a few Deere pumps and motors for this reason)
What kind of flow rate should I see if I was to hook up a flow meter?

Good day Jason
The fan speed is variable controlled by the ECU via a PWM valve it is possible to by-pass for trouble shooting, do you have any errors in service mode ?
Kind regards
Uffex

On the back of the fan , right beside the motor, should be a speed sensor. It should read a window cut into the back of the fan hub. Check your plug and wiring. Make sure nothing got pulled apart, broken or torn.
Trace hydraulic lines back to pwm valve described by uffex . If you unplug, while running, you should see/feel/ hear the fan speed increase. If I remember correctly, the pwm is fail to open. You are absolutely correct, you are not shedding enough heat at the radiator. I would be curious if you have reversing fan option.
How many hours, what kind of work? What's your boost running under load, any chance of a compromised head gasket? BTW the instrument panel shows straight up good till you reach overheat threshold then bury in the red. Do you know how to access service screen to see actual numerical values?

I did acces service mode, does not appear to be any codes I can find. I’m a Deere trained guy not a Volvo guy. On my own now trying to work on it all.
I did not notice a speed sensor on fan but maybe not looking in correct spot.
I will have to locate pwm valve and try the unplug diagnostics to see if it speeds up.
6600hrs on unit
Working in gravel pit stripping overburden and piling pit run for loader to feed crusher is what unit is being used for.
Did not check boost pressure directly but doesn’t seem to be underpowered and not smoking under load so I assume boost is good. But need to verify some numbers.

With those ambient temps, coolant temp should drop like a rock as soon as t stat opens. Fan should be screaming if temps over 210. 217 is alarm threshold, if I remember correctly. You could also find hydro fluid temp sensor on lower part of tank. Unplug that and fan should go max also. You'll also trigger sensor loss errors.

funwithfuel said:

With those ambient temps, coolant temp should drop like a rock as soon as t stat opens. Fan should be screaming if temps over 210. 217 is alarm threshold, if I remember correctly. You could also find hydro fluid temp sensor on lower part of tank. Unplug that and fan should go max also. You'll also trigger sensor loss errors.

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Sounds great. I will be back to unit in next couple days. Fan is not screaming ever when temps go up. Which I find odd. Especially with no codes.

UPDATE
was at unit yesterday. Located PWM valve under fan. Unplugged fan motor and right away got a fan system failure code on the dash. Which I’m happy knowing that part of the system appears to be ok. The fan should fail to high speed at this point and did nothing. Just ran slow like before.
There are no active codes for anything. Any new codes I found were generated by me screwing around.
I’m thinking the PWM valve itself is bypassing all the time. Stuck per say.
That or motor is nfg?

Good day Jason
Please see attached should help.
Kind regards
Uffex

Do the rpm's change at all when you unplug the fan control? Have you checked fan speeds with a photo tach? Does this have reversible fan option? Reversible fan will be different than standard option and will not have the check/anti-cavitation valve in the motor. The reversible fan valve will have 2 coils on the valve and the check valve will be inside the valve.

The motor does not need to be disassembled to check the anti-cav valve. There will be a plug on the side of the end plate you can remove and check it. The reversible motor will have a plug with an adjustable stem. This needs to be screwed in all the way so there is no leakage inside the motor.

You can always bypass the fan control valves and check for operation that way. Just do not run them for very long as you will not have anti-caviation protection for the fan motor.

UPDATE AGAIN
PROBLEM SOLVED

Pulled PWM cartridge and found it to be stuck open. Upon further investigation found a small maybe 1mm or smaller stone wedged in it in one of the holes. Cleaned that out and all works again as per normal. And man does that fan put out at full speed !!!!!! Yikes.

Good/great catch. Glad you found it without too much hassle.

Jason B said:

UPDATE AGAIN
PROBLEM SOLVED

Pulled PWM cartridge and found it to be stuck open. Upon further investigation found a small maybe 1mm or smaller stone wedged in it in one of the holes. Cleaned that out and all works again as per normal. And man does that fan put out at full speed !!!!!! Yikes.

Click to expand...

Good News and some good suggestions to check on these hydraulic fans. Use to live in Rocky Mtn House.

Jason B said:

UPDATE AGAIN
PROBLEM SOLVED

Pulled PWM cartridge and found it to be stuck open. Upon further investigation found a small maybe 1mm or smaller stone wedged in it in one of the holes. Cleaned that out and all works again as per normal. And man does that fan put out at full speed !!!!!! Yikes.

Click to expand...

Hi jason. Hope you doing well. My excavtor volvo 210 model 2015. I am having the same issue withe overheating. Can you explain more pwm cartridge pls. I clean radiator, changed water pump, fill radiator withe coolant but still my excvator heating up.. thanks in advance

Best regards

Good day
Please see attached, I assume you have an EC210C machine.
Kind regards
Uffex