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.

[RichCam]

I'm not an experienced Iltis driver but the manual says to keep it always in 4 wheel drive. Is that a good idea when you are on a paved highway cruising along at Iltis highway speeds?

[rob love]

Not necessary. The army did it as a safety precaution. The instructions were that you would go to 2 wheel drive if doing tight maneuvering on hard ground such as a parking lot. On dry pavement, there is no need for 4 wheel drive at any time. I remember changing a lot of worn axle joints on the regimental police Iltis which was regularly operated around camp. The bulk of the Iltis just went down the highway and into a training area.

In the icy season though, or when things are wet, it might make sense.

Note when shifting back into two wheel drive, you merely flop the lever forward and let it pop in when it's ready. If you force it, you will bend the linkage and be stuck in four wheel drive. I straightened many many many of those over the years.

[RichCam]

Thanks Rob for the 4x4 advice. Maybe the Iltis will get a little better fuel mileage in 2x4 rather than 4x4?
So, mileage can only be measured if you know how far and how fast you are going. This Iltis also has a non functioning speedometer. I was told that the speedometer needs to be replaced by the owner and he has a replacement. Problem is, it isn't the speedometer, it was a frozen speedometer cable. By freeing both ends of the cable, dumping in some anti-seize and twisting the cable cover, I was able to free the cable. Inserting the transmission end of the cable into a cordless drill and activating it registered on the speedo. It appears that the speedo drive gear is pooched (stripped) and I have a replacement gear on order. I actually have 2 on order in case someone else needs one. They should arrive next week.

[rob love]

The problem with 4 wheel drive all the time is that it would depend very much on tire pressures being at the proper pressure, based on load (which can vary), so that the deflection is even between front and rear. Even then, sharp turns result in a different turning radius between the front and rear wheels. So yes, driving in two wheel drive will save some fuel and definitely save some mechanical wear over the long run. The only wild card is if the Iltis driver ends up in accident that 4 wheel drive might have prevented, then any savings are negated.

Certainly, disconnecting the front axle for the summer months would be a good idea. Are there people actually driving these things in the winter? Mind you, I used to drive a M38A1CDN to work during a Manitoba winter, so who am I to judge? Just seems to me that if someone was driving an Iltis in the winter in Ontario or Quebec, the vehicle would turn into swiss cheese from the rust within a few seasons.

Tell the Iltis owner not to toss that new speedo head. They were problematic as well. But it is certainly a good idea to perform proper diagnosis before ordering in expensive parts.

[RichCam]

Rob,
This Iltis is well cared for during the winter! It has it's own storage shed, dry floor and is put away before the salt hits the road. Right now, it is in my workshop and I will only take it out for a test run when it is nice and dry. I am hoping to work out a deal with the current owner to "borrow it" for some events next summer. It should be "exercised" to keep it in good running condition.
When I have it all buttoned back up, I'll post a couple of pictures. It would make a cool kind of summer to and from work driver!

[rob love]

Originally Posted by RichCam

Rob,
It would make a cool kind of summer to and from work driver!

Get a Willys....you will spend a lot less time in the shop.