Military engine - what is this part?

[SeriesShorty]

Hey all, I'm trying to sort out a weird groaning noise coming from the engine. It is loudest at the front drivers side of the radiator (certainly it can't be coming from the radiator itself). I'm narrowing it down to the water pump or this pulley thingy that I have circled in the diagram attached. What is this part called, some type of idler pulley, etc.? I want to search exploded diagrams for this as I'm sure there is a bearing in there that could be causing this noise but I can't find anything on it.

Thanks all!


Also note to self: don't take the bonnet off for painting without checking weather first. 4 days of very heavy rain will make poor truckie run like poo.

[greenmeanie]

I don't know about the part you are talking about but I do know that a common source of graoning on military engines with an oil cooler is the regulator valve for oil flow to the cooler.

[luckyjoe]

Greenmeanie is right - it is the valve at the oil cooler inlet. You get a little groaning when it's partially open.

Regards,

[SeriesShorty]

Thanks G! At least because of your information and me then searching for an oil cooler regulator I came across the part that I had in question...it's the water pump tensioner.

So I'm not crazy about the noise sounding like it's coming from the top right of the radiator then. That I assume would be the location of the oil cooler regulator valve. Oh geez, that already seems impossible to find a new replacement for. Is being partially open considered defective??

[teechizpet]

Groaning from a military oil cooler is quite normal.

[Jim-ME]

My oil cooler groans all the time and when you first hear it, unless you know what it is, it can be quite disconcerting.
Jim

[lrdukdog]

groan

Groaning from a military oil cooler is quite normal.
How can the SAS sneak around behind the lines with all their Landy's Groaning?
Jim Wolf

[SeriesShorty]

LOL It is pretty loud and disconcerting, I definately won't be sneaking up on anyone!

But thanks for relieving my concerns and I'll just learn to love the weird noises my truck makes...as if a Series didn't have enough of those already.

[hughwilton]

I disconected mine a couple of years ago with no ill effects. I don't think the cooler is needed for 99% of my activities including desert driving. I also never felt the need for one on my previous series trucks, which I worked harder than this one.

[JimCT]

oil cooler

One of the best things you can do for your engine is keep the oil cool. I would not disconnect the cooler. Actually after a few years of running Mobil 1 in our ambulance it never makes a noise now.

[jac04]

One of the best things you can do for your engine is keep the oil cool.

...or you can achieve the same results by selecting the proper oil for your operating conditions/temperature. If you are running at higher than 'normal' temperatures, there are a lot of excellent synthetic oils out there that can provide proper viscosity at elevated temperatures while being very shear stable. Check out German-made Castrol Syntec 0W-30 for example - aka "GC" - (don't let the weight designations scare you). Mobil 1 0W-40 is also an excellent choice, and is the only Mobil 1 oil I would consider using (unless they have made any recent changes to the 10W-30 and 10W-40).

Lots of good oil info over at www.bobistheoilguy.com

[SeriesShorty]

It sure has been difficult to time/tune my truck cause the groaning noise was SOOOOO loud at idle!!!!

Last weekend I changed all my fluids and dropped the oil pan to clean up and reseal it. After putting it all back together the groaning noise has stopped. I mean, totally stopped. I noticed the bolt holding the cooler line to the pan had a hole through it which I assumed would need to be lined up with the direction of the hose to allow the flow of oil through the line. I marked the bolt so that I could snug it up with the hold aligned with the hose.

Was that correct or have I blocked the flow of the oil into the line by doing so? I assume the only reason the groaning would have stopped was if the oil was not flowing through the annoying groan producing valve.

Good news is the leaky pan is no more...for now anyways. And it idled so quietly today that I got the ignition timing and the carb adjustment much better than before! First time I was able to drive any distance in two months.

[SafeAirOne]

...it idled so quietly today that I got the ignition timing and the carb adjustment much better than before! First time I was able to drive any distance in two months.

Did I miss the post where you told everyone what the cure for the original, post-rainstorm difficulty was? Was it the valve spring in the carb?

Sounds as if you've got it purring like a kitten now--Congrats!

[SeriesShorty]

LOL My rain related issue actually took out my voltage regular sending the full 24v to the coil thus frying it and probably the points, too. But that was a different challenge. It's been a very interesting 2 months sorting all my issues out.

The carb actually seemed to settle itself out, maybe the gaskets just finally got wet enough to seal better or the action of me constantly pumping the throttle to keep the thing running loosened up the tight spring. I hadn't gotten around to taking the carb apart to play with it anymore. It still needs a little more work, but now I have a much better basis for adjustments.

Funny thing is, with all the groaning gone from the oil cooler, I could finally hear the engine idle and knew something was wrong there. Earlier in the day I found a dwell/point/tach meter at a yard sale for $1. I managed to get the truck started and warmed up and figured I would play with my new toy. I tried the tach first. Ummm yeah, I was only idling around 200rpm! So I was trying to set timing on a truck that idling too low. The right tools make a huge difference! Once I got the idle up high enough, I reset the timing using the "beer" method that has recently been chuckled at. Except I used the fuel in the clear fuel filter as my "beer." Tightened it down and the truck is now running better than it ever has in the almost exactly one year that I've owned it. I spent the entire day driving around St. Louis and it's suburbs and just got back home.

It was a good Rover day!

[Tsmith]

stethescope

A mechanics stethescope isn't a bad tool to have. It can be difficult to tell exctly where sounds are coming from. They are inexpensive (NAPA)and have a variety of probes to contact hard-to-reach places on the engine. On the Disco, I was sure that the power steering pump was gone....a costly repair but not uncommon. It turns out the tensioner was all that was needed.

In addition, hanging one around your neck makes you look a very knowledable and thoughtful mechanic. People will solicit your advice.