Linde H45T 394 Series (VW LPG) Overheating, Cooling System Problem

[Millworks]

Linde H45T 394 Series (VW LPG) Overheating, Cooling System Problem​

Hi, I have a Linde H45T which overheats and shuts-down after 10-15 minutes. At which time coolant overflow it evident. I presume this is due to the coolant overheating? ... I should point out that I'm somewhat mechanically challenged.

Subsequent steep learning curb, I serviced the engine oil and filter, air filter, hydraulic oil filters (X2) and replaced the water pump. Even though the internal rotor blades of the pump were broken, the new replacement did not seem to resolve anything.

I also flushed the radiator which had the incorrect (green) coolant and renewed with the correct red coolant and demineralised water. Even though I flushed the system several times before refilling with red coolant, it expelled pure green coolant upon first trial run, post the water pump and coolant change-over. I'm only mentioning this in case it may indicate a blockage issue?
The radiator fan seems to operate OK, but I believe that there is a secondary auxiliary water pump and fan which operates when unit is turned off etc? I don't believe that this fan is operating. I have no idea where this fan is located, but I presume that I should be able to hear it. Should I now focus on the thermostat?

Lastly, could a poor battery cause related issues? If so, I should divulge that I'm relying on jumpstarting, thinking that the battery will come good once I am able to run the unit for more than 10 minutes at a time.

Any advice would be much appreciated.

 

[Lindetech419]

Is the fan turning when running ?
Did you replace thermostat?
If you did was it same temp as old ?
When they overheated it was usually due to fan not working or thermostat issue

 

[Millworks]

I finally replaced the thermostat (and housing). The old one looked to be in good condition at first glance. However it was about 5 times hard to depress the spring valve than the new replacement. I'm guessing that means it was cactus? I've only just now let it run up to temperature while conducting a system flush.

It all seemed to be going OK:
1.) after a few minutes I noticed that the LPG regulator was frosting up which was a bit alarming
2.) then the fan finally kicked in and the regulator defrosted fairly quickly so I kept it running
3.) fan disengaged and engaged (as I believe it should) ... regulator was remaining frost free
4.) I was just about to turn it off after approximately 10-15 minutes to finish the flush procedure, but it went into auto shut-down
5.) *** Regulator was extremely hot ... doesn't seem right?
6.) no signs of system leakage
7.) I'll now drain the system, but I'm guessing that I should hold off refilling with new coolant?
8.) also I just noticed (in the Parts Manual) that there's mention of what looks to be a cartridge filter in front of the radiator?

 

[Lindetech419]

The lp vaporizer will get hot enough to burn you ,that is normal. As far as fan it will kick on and off as the unit runs it is activated by a temp sensor that is set at a certain temperature . The cartridge filter will have nothing to do with boiling system

 

[Lindetech419]

Cooling system

 

[Millworks]

Thanks for that. Considering your comment regarding the operating temperature of the vaporiser, I should point out that this was the sole reason I presumed it was overheating. The system didn't bubble over as it was doing prior to the replacement of the thermostat. Is the thermostat sensor a possible culprit? I was thinking yesterday that it would have been a good idea to replace it while doing the thermostat, even though it looks fine? Lastly, and this is probably nothing, but I drained the flushing agent by removing the lower hose connecting in and under the auxiliary pump. The water that ran from the pump was fairly hot (after sitting dormant for an hour or so), while the water that came out of the disconnected hose was fairly cool. I appreciate that I'm grasping at straws. Thanks again

 

[Lindetech419]

As engine cools the thermostat will close trapping warmer water in the engine . water will be hotter than that in hose or in radiator . The upper hose and water will be much cooler than lower hose and water as far as sensor
It wouldn’t hurt to replace it as a precaution I’m assuming you are referring to the fan sensor as there are two sensors one for fan and one for temp

 

[Millworks]

I was referring to the sensor next to the thermostat?

Could I still be looking at a blockage somewhere. I'm guessing that the functionality of the auxiliary pump would have no bearing on it?

Should I just fill and test run with the new coolant and maybe I had an air pocket last test? Cheers

 

[Lindetech419]

That most likely is the temp sender
What type of coolant are you using ? Vw recommends the pink - red coolant
Is the radiator fins open for air flow?
If all looks ok , fill and test run I always replaced water pump with timing belt
I changed ours (35) units every 2000
Hours because they were rental units that belonged to us and we were not prepared to eat a head or an engine
Also I found if I used mobile 1 oil the units ran better and cut down on engine noise ( lifter- pushrod clicking ) I also found a couple of rebuilt water pumps that the fan turned on shaft Linde only sells new pumps because of this you can get a rebuilt one from VW or parts house but not from Linde if you do purchase a rebuild be sure and check the fan for tightness on the shaft
If you have or have access to a laser thermometer that’s what I used to see what radiator etc were at temp wise
When it shuts off does it throw a code on display or over temp icon ? The laser will tell you if you are actually overheating or a bad sender etc
Hope this helps and doesn’t overwhelm you with info I was the trainer at my company so I tend to go far into things at times sorry

 

[Millworks]

Ha ... I'm way past the point of being overwhelmed ..., but that's to be expected with "steep learning curve(s) for the mechanically challenged" such as myself ... so all good.


I'l go and give it a tester now. And yes I'm using a red coolant compliant with the VW spec (concentrate plus distilled water - hopefully same/same as pre-mix?) I'll let you know how it goes and I'll look out for a code, but I think that my system needs resetting if that's a thing?

Additionally I just noticed these dodgy wires (as attached). This is the sensor and plug neighbouring the thermostat housing. I would love for this to be the cause of the issue, however it looks as though there is clearance between the exposed wires ... even though this of course needs to be addressed. Cheers

 

[Millworks]

RUN RESULTS:

All seemed to be good ... unfortunately ended with auto shut-down.

I've attached a photo of the digital display:
1.) the icon on the righthand side of the hours was flashing, while the spanner icon was solid
2.) the above applies to both when running as well as post shut-down

At the risk of sounding even more challenged than I really am, I just reviewed coolant info and ...

1.) states 2.9L of G12 plus 4.2L of water
- providing a total of 7.1L ... leaving me with 2 issues:
1a.) unsure of how I used a total of approximately 10L?
- I don't have a maximum line on the exp res ... just a minimum?
- am I overloading? ... either way something is a miss ...
1b.) looks like I've also stuffed up the concentration mix:
- I used approx 4L of G12, BUT in concentrate and approx 6 plus L of distilled water
- I thought I was working around the recommended 40% mix, but now I realise this is based on pre-mix? ... yes, very blonde

If you tell me the above could well be the cause of my problems, I'll be only too happy to take any slander which may come with. Cheers

 

[Millworks]

Radiator Fan (questionable):
I believe the fan may be the issue (and/or associated controllers/sensors). I purchased a digital temperature this morning to do another test run and check temps, but didn't get far enough to take temps. The fan is now engaging immediately upon cold start (on low) and I believe that even though the fan hit high speed during yesterdays test run, it wasn't running at high speed prior to auto shut-down.

Also noticed today that I could easily stop the fan with a light touch of a finger. Then it only took a very light finger flick to kick it back into action. At that point I shut it down. Prior to this run I also disconnected and confirmed the non return valve was all good.

So does this now point to the hydraulic motor and/or bypass valve, or associated controllers / sensors? Apologies for the drawn out exercise. Cheers

 

[Lindetech419]

Unplug fan sensor wires and start unit the fan should run on high speed immediately and you shouldn’t be able to stop the fan with little force
You may have a hyd pressure issue going to fan motor