Howdy- This question is not actually about my 6BT Dodge, but rather about an International Scout that I dropped a 4BT into. I have tried this question over on the 4BTswaps site, but haven't gotten too much response. DTR has always been good to me and my Dodge, and the engines are virtually identical, so here goes...

The reason I write that I could use some HELP is that I am on a road-trip in the 4BT Scout. Not only do I need to actually get home, but dumping out clouds of white smoke everywhere I go in Reno is a real drag....

The title of the thread pretty much explains the problem. The 4BT is putting out a whole lot of white smoke... especially on revving the engine, but all the time really. Also, the coolant temperature gauge shows that the coolant temperature is not getting very warm, compared to "normal". (This is the stock gauge from the Scout, so no actual temp numbers on the gauge face)

Here are a few other details...
A few days ago on the way through Arizona I plowed into a pretty big snow bank, and the wire to the electric fan got ripped. As far as I know, that fan has never turned on, so I didn't fix the wire at that point. Then, later in the day, I was waiting in a really long, slow line to get into the Grand Canyon and the coolant temp gauge showed higher than ever before, but still only about half-way up the gauge. When the gauge reached that point it stabilized, even though I was still in line for another 10 or 15 minutes.

Today I put a piece of cardboard in front of the radiator, completely covering it. This helped the temps get up a little higher, but they are still considerably below normal. This might have helped the smoke a little, but not that much. I also changed the fuel filter (even though my fuel pressure gauge said I didn't need to) and this helped a little, but not much. Still lots of smoke.

I checked the oil, and I see no evidence of coolant at all. It's also not low. Also, I smelled the smoky exhaust, and it didn't smell like oil, and it didn't really smell like diesel either. It had a smell, I am just not sure what it is.
Engine power is normal, EGTs are normal, boost is normal.

Could the thermostat be stuck open??

I need the truck to get around, and to get home. Any help would be appreciated.

Christian

 

first thing that came to my mind was the thermostat. they usually fail open... at least newer ones. I find that usually the most simple answer is usually the solution.

 

Thinking that the smoke could be coolant from a blown head gasket, I went down and checked the coolant. It is low, but not super-low... about 3 inches down from the filler neck.

However the coolant looks pretty awful. It's sort of brown and grimy. BUT, I did add some Bar's Leaks a few days ago, and the coolant looks more like Bar's Leaks than oil. It also does not really smell like oil. Also, there is NO sign of coolant at all on the oil dipstick.

What other test can I do to check for a blown head gasket?

Christian

 

Pull the water plug out on top of the head and fire the engine without the belt for a few seconds. If you get bubbles without the pump spinning you've got a compression leak.

 

dont know if it will be open today. but there is a Cummins almost to s. mccarren heading down e. glendale. you can get a thermostat from them and try that.

 

Thanks. Went there today and bought the thermostat and seal. Gonna try to change it out here tomorrow, even though I really don't know anyone or have a place to work here.... and it's cold out!

Hopefully that will do it.

Christian

 

lol from Cummins if you keep heading down glendale to Summit they have a big dirt/gravel parking area where you can work on it. AND you can walk over and buy a tool if you need one!

 

When I did my swap I had the same problems. It was the thermostat. It is a fairly easy fix. Another thing I would look at is your temp sending unit. Buy one for the Scout and get what ever bushing you need to adapt it to the Cummins block. My guess is you will never get the "right" reading if you are using the Cummins sending unit.

 

i have had that same problem with my 82. been driving 6 years with a cold engine. 3 different cummins thermos. 85 degree day, 20 miles, infrared thermo average temp on block 125 degrees. NEVER in my 40 plus years experience in the business have i had an engine that i couldnt make run hot. been driving without a fan the last 2 years even in 90 degree weather.

 

OK, so the newly installed OEM Cummins thermostat didn't change a thing.

I have just driven 1200 miles back from Reno. I was able to keep the engine temps in the normal range by covering approximately 95% of the radiator with cardboard.

The amount of smoke gradually increased over the last few days, and it is absolutely burning oil. It smells strongly of oil and I had to add about a quart of oil every 300 miles or so to keep the level good.

THIS INDICATES A FAILED HEAD GASKET, RIGHT ??

I need to know what this is before I tear into it.

Christian

 

well your exhaust shouldn't rust out, now with that fresh coat of oil. I'd say pull the turbo and swipe your fingers in the manifold to see if its from the motor and not the turbo. You may get lucky and just need a new turbo seal kit. If it was mine it would definitely be the head gasket, thats just my luck.

 

As a long time binder nut, and mopar nut, Why on gods green earth would you use the scout gauge??? They were crap when they were new. Go get a mechanical gauge and screw in there..

 

What he said, make sure the oil smoke is not a bad turbo.

 

OK, thank you for these good ideas. Obviously the Scout gauge, with no actual numbers, is not the way to go and might have been a major cause in this whole situation.

The turbo was acting strangely during the entire trip. While it is tempting to think that all the problems might be caused by a funky turbo, the fact is that the turbo started acting strangely BEFORE the other symptoms appeared. This suggests that it may not be the sole cause.

Here is what the turbo was doing: Sometimes when slowing down, there would be a short noise which sounded like a shaft sloppily spinning in a bearing (if you have ever put a die-grinding burr bit in a hole that was slightly too small, and had the high-speed bit "spin" uncontollably around the hole, it sounded sort of like that). Typically, after hearing that noise, the next time I stepped on the gas there would be A) no boost, B) rapidly rising EGTs, and C) a sound like a turbine winding up, which was proportional in pitch to the engine RPMs. Interestingly, this "turbine-winding-up" sound would occur only when the turbo was apparently not working. Sometimes if I switched gears, bringing down the RPMs, or more reliably if I just went into neutral and let the RPMs come down to idle for a few seconds, the problem would go away, i.e. the turbo would start working again.

I do not really understand the mechanism that might be causing this particular problem, at least in part because I have never taken apart a turbo. But my best guess (some of your guesses will invariably be better) is that the bearings went bad or they were not getting oiled or something like that, and the turbo was somehow "sticking" intermittently.

It did occur to me on the trip that the problems might have been caused by whatever was going on with the turbo, BUT.... I cannot see how the turbo could explain the other main symptoms.

These symptoms are:
1) A clear "missing" sound from the engine
2) Engine's inability to maintain heat
3) Oil-smoke also coming from the crankcase breather, from oil dipstick tube, and oil-fill cap (all pointing to blow-by oil-smoke in crankcase)

These point towards SOMETHING else. I will have to get into it.

Any other ideas based on this new information?

Thanks,
Christian

 

1) Could also be explained by a stuck injector.
2) Does not really point to a HG failure
3) Does this engine have a rotary vacuum pump and is it connected to anything?