Iltis Overheat Question

[RichCam]

A neighbour dropped off his Iltis for me to take a look at. Nato# 8101118486132 WVWZZZ18ZCA00770 Contract # 50TL3613030 It came with the operator's manual but not the service/repair manual. Upon starting, it reaches a very high temperature quickly. The electric fans seem to be functioning correctly, the temperature gauge reads 120+C and the upper rad hose is hot. Does anyone have any suggestions/diagrams/procedures on where to start? I'm thinking that a malfunctioning thermostat might be a suspect.
Thanks in advance,

[Yeo.NT]

I would start with check the tempature across the entire cooling system, a laser thermometer helps if you have one.
- If the upper rad hose is hot, Is the lower rad hose cold/warm/hot?
- What is the tempature across the radiator? Hot on one end cold/warm on the other?
- Is the water pump belt tight/serviceable?
If there large variation of tempature it could point to either a clogged in the system or bad water pump

[rob love]

The cooling system on the Iltis was somewhat marginal. A common problem was that the antifreeze, if run pure, would cause it to overheat. Ensure the antifreeze is at a 60/40 mix.

The fans, although both on switches of the same temperature rating, will come on sequentially, the second one only coming on if the first one can't do the job.

I had heard of impellers working loose on the Iltis water pumps, but I never actually saw one myself.

[RichCam]

Guys, thanks for your advice and the ecopy of the maintenance manual Stuart. When I took the thermostat cover off, I discovered a big piece of melted plastic stuck in the thermostat spring - not good. Worse, someone had already tried taking the thermostat cover off before me and twisted off one of the bolt heads. Drilling out the stud, upside down and on a angle with a hand drill was next to impossible so I removed the water pump. An adventure to say the least because I did it without removing the alternator. It is not my Iltis so I didn't want more things twisting off and breaking...... I purchased a new water pump and a new thermostat, installed the water pump and installed the thermostat and cover. Unfortunately, the old thermostat cover doesn't exactly fit over the new water pump opening for the new thermostat and it leaks at the edge after I filled it. I am going to replace the tapered rubber gasket that fits over the thermostat cover with the supplied o ring, I will make a new gasket that is slightly bigger than the outer dimensions of the cover and I will use gasket goop between the metal pump housing and the hand made gasket. Correct me if I am wrong, but I hope this will provide sufficient "gap" stoppage to prevent leaking while under operating conditions. Suggestions Welcome!
Regards, Richard

[RichCam]

If you buy an aftermarket water pump for the Iltis, you had better purchase an aftermarket thermostat cover. The original cover is just slightly different and it is enough to cause an antifreeze leak. I got everything else hooked up and did a road test. Within 5 minutes, the temperature was again up to 200. When I wheeled it back into the shop, I hand tested all the hoses. No leaks and all were hot including the cold return from the bottom of the rad. After consulting the maintenance manual, I removed the rad after draining the fluids. Looks like someone was driving around in a silty river! The rad is now at Bracebridge Radiator for flushing and cleaning. Hope to have it back in the Iltis next week.

[rob love]

Iltis fun never ends.