Bobcat 863 Deutz 1011F Overheating

[obleck]

Hello everyone, thanks for suggestions on other past topics/

I've picked up a late 90's Bobcat 863F and pretty much fixed up everything except it's overheating. I'm new to this particular engine, but a pretty reasonable amateur mechanic. Some details:

- Deutz 1011F
- Runs okay at low throttle, but temp slowly keeps building under heavier operation to temperature red-line. There is an engine temp overheating light that also turns on.
- It's got about 3300 hrs, runs strong, plenty of power, etc.
- I've pressure washed it extensively, including the drive belts/pulleys/etc, which were all pretty caked
- Oil level reads normal.
- The cooling fan is working, blows strong.
- The radiators look clean, but I'm going to pull the engine oil cooler out entirely to check its backside
- *** When it gets hot, a LOT of oil is weeping out of the fuel injector area at the top of the engine, which is baffling to me.
- I have not been able to check the oil pressure yet, but that's next too.

It would appear that there is a clog somewhere. I think I'm going to drain the oil and see what else I can find. I read somewhere there are three different thermostats that can get clogged. Can anyone chime in on that? The Deutz manual isn't very revealing.

Thanks in advance!

 

[obleck]

Here's a shot of the engine from the back of the machine. Oil is weeping from the injectors and valve covers when hot. Could this be a sign of a clog?

 

[Vetech63]

We need the entire model number. There are quite a few 1011 series engines and they have differences. There should be letters and numbers before the "1011F"

 

[mg2361]

That engine uses engine oil for the cooling system. Have the temps going into and out of the radiator been checked?

 

[obleck]

The engine according to Bobcat specs is a BF4M1011F, though I could not find a placard.

I started today by draining the oil, which is done through a little extension pipe from the oil pan in this machine, I was surprised that it drained VERY slowly. I would say, in 45 min it drizzled out about 2 gallons, and is still dripping. The oil is very black, needless to say. Is it possible this engine is filled with gunky/tar/oil? If so, what's a good way to flush it? Any sort of solvent additive that I can throw in there with some new oil and then drain again after bringing it to temp for a bit?

I haven't been able to remove the thermostat yet--didn't have the right allen wrench.

I'll check the temps on the oil cooler intake and discharge next time I have it hot.

 

[obleck]

I did some reading around on using diesel fuel to flush with, and most people report good results. I'm thinking 50-50 or so? I figure idle for 15-20 min, and then drain and see where we are, maybe rinse and repeat?

 

[Swannny]

I've owned a ton of the deutz 1011 engines. Last one I had in a gehl was overheating. Ended up being a combination of things: fan blades were chewed up with chunks missing (still pushing plenty of air), oil cooled radiator clogged on inside face, fan belt slipping, muffler was leaking inside engine bay pretty good. Never had a T stat go bad yet.

Use a laser thermometer to check for true temps in different locations as the temperature guages are often inaccurate (reading high many times). These oil cooled engines can have head gasket issues if overheated like any engine - check for blow by in crankcase.

 

[obleck]

Update:

I changed the oil with a mixture of oil/diesel and brought her up to about 230 on the gauge over about 15 min. I then drained it again. This time it drained much quicker, but of course the diesel helped. The areas around the injectors also started weeping oil again at temp.

I pulled the hydraulic oil cooler out, leaving the engine oil cooler. I discovered the following:

- both the inlet and outlet are at the higher end of the radiator, and hence it can collect sludge and whatnot. Interesting--was it deigned that way on purpose?
- the inlet became very hot to the touch, though I didn't have a laser thermometer handy. I hope to next time.
- the outlet was barely warm
- parts of the radiator were warm
- the fan was blowing air out of the the two side vents with authority, BUT, it was pushing some air through the radiator, as opposed to creating negative pressure. Is this what it should be doing? I wouldn't think so. I don't know where the air it is blowing out is coming from, but it's not passing through the radiator. I am guessing there is a broken or missing shroud of some sort, though it's hard to tell from the parts drawing what it might be.
- I opened up what I thought was the thermostat (just below the oil filter), but it was some sort of valve. I pulled it out and another cup or so of oil drained out.

My plan for next time before running, is to pull the engine oil cooler and flush it as best as possible, take a look at the fan system, and also inspect the thermostat.

 

[obleck]

Update:

I took out the engine oil cooler, dumped out the oil that was in it (not that much came out, so maybe it is somewhat clogged), blew some compressed air through it, filled it with diesel fuel, and am letting it soak for a day or two.

Took out the thermostat, which looked okay, but I'm replacing it anyway.

The fan system looks fine, but I can't understand where the air that is blowing out the exhausts is coming from if it's not through the radiators. There are openings underneath the impeller that go into the engine compartment, but the impeller has a flat bottom that covers it entirely, so there is no way it can pull air from there (push air into it, yes, or possibly some sort of venturi suction too).

Cleaned old grime from the radiator areas, but not so bad as to cause the problem. Also, the radiators were not clogged.

 

[obleck]

Okay! To wrap this up:

I got 'er running at a solid 228F on the gauge in about 90F ambient.

What I did:
- replace thermostat (note that the bobcat replacement thermostat is a little longer than the original, and hence there is a special plug that you have to replace too. The dealer in Reno happened to know this fortunately).
- flushed engine with 50/50 diesel/oil--brought it up to temp and then drained
- took out the engine oil radiator, filled it with diesel, and let it soak for a couple days, drained, lightly pressure washed, and reinstalled. It wasn't very dirty on the outside, but I just wanted to get the spilled fuel/oil off so that it wouldn't collect dirt as easily.
- opened up the oil valve of some sort below the oil filter, and just made sure it was clean
- replaced oil filter and oil
- cleaned out dirt from the fan/stack area, though it wasn't hindering airflow really
- replaced the temp sender.

Additionally, I was perplexed because when I ran her with the hydraulic oil cooler off, it felt like air was blowing up, _out_ of the engine oil radiator, rather than being sucked through it. However, finally I tossed a rag on it briefly and it sucked right down, so clearly the fan, which is blowing plenty, is doing the right thing. I guess there is a lot of turbulence on the outside of the fan which can make it seem like there is air blowing out when there is actually substantial net suctions.

Anyway, she warmed up to 228 and stayed right there, to my delight. Warm air blowing out of the side vents.

The oil leaks on the side of the engine in my initial picture, turns out, appear to actually be a leaky diesel fuel return line. Replacing it next time.

I'll keep an eye on it and report back if the problem isn't solved after all.

Thanks all for the suggestions.

 

[Swannny]

Typical operating temps for me on an upper 80’s degree day **while mowing** with a 72” bushhog attachment is 200-205 degree engine oil temp and 150-160 degree hydraulic temps.

 

[obleck]

Typical operating temps for me on an upper 80’s degree day **while mowing** with a 72” bushhog attachment is 200-205 degree engine oil temp and 150-160 degree hydraulic temps.

Interesting, thanks. I wonder if my temp sender could be off too. I replaced it, old one was dead I think. 205 seems low though. These engines are rated to run pretty hot, or so I read somewhere.

 

[Tom Stephenson]

Okay! To wrap this up:

I got 'er running at a solid 228F on the gauge in about 90F ambient.

What I did:
- replace thermostat (note that the bobcat replacement thermostat is a little longer than the original, and hence there is a special plug that you have to replace too. The dealer in Reno happened to know this fortunately).
- flushed engine with 50/50 diesel/oil--brought it up to temp and then drained
- took out the engine oil radiator, filled it with diesel, and let it soak for a couple days, drained, lightly pressure washed, and reinstalled. It wasn't very dirty on the outside, but I just wanted to get the spilled fuel/oil off so that it wouldn't collect dirt as easily.
- opened up the oil valve of some sort below the oil filter, and just made sure it was clean
- replaced oil filter and oil
- cleaned out dirt from the fan/stack area, though it wasn't hindering airflow really
- replaced the temp sender.

Additionally, I was perplexed because when I ran her with the hydraulic oil cooler off, it felt like air was blowing up, _out_ of the engine oil radiator, rather than being sucked through it. However, finally I tossed a rag on it briefly and it sucked right down, so clearly the fan, which is blowing plenty, is doing the right thing. I guess there is a lot of turbulence on the outside of the fan which can make it seem like there is air blowing out when there is actually substantial net suctions.

Anyway, she warmed up to 228 and stayed right there, to my delight. Warm air blowing out of the side vents.

The oil leaks on the side of the engine in my initial picture, turns out, appear to actually be a leaky diesel fuel return line. Replacing it next time.

I'll keep an eye on it and report back if the problem isn't solved after all.

Thanks all for the suggestions.

Hello. I know this is from 9yrs ago and wondering if you ever found the issue with your bobcat? I have a 2000 model yr 863 with the deutz engine. Great machine but have been having heating issue this yr. I have checked thermostat, cleaned rad, blows good air, changed to a lighter oil and thought I had the issue solved with the lighter oil but today it was heating up again. Just wondering if you ever came across the real issue with it heating.
Thanks for the help and info.

 

[BobCatSkid]

Bobcat 863H '97 model with a Deutz BF4M1011 engine. I am fighting an over heating problem. Just received the new thermostat from Bobcat. Mr. obleck's 9/26/20 post is spot on. Deutz has made a design change to the thermostat. It requires a new plug, PN 7022637.

Bobcat's parts website is wrong. Bobcat said that they will update the website to show the new plug. The old plug has a flat face. The new plug, per Bobcat, has a blind hole drilled into the end that mates to the thermostat.

Hopefully, I can get my skidsteer working by the end of this week.

 

[BobCatSkid]

Just to end out my portion of this thread....

I did install the new thermostat and plug. My overheating problem is fixed. I have used my skid steer several times now. Temperatures are now running normal per the Bobcat display.

After running the machine for several hours, I measured 193F at the thermostat plug with a thermocouple.

 

[Simon C]

Thanks for sharing the solution. May help a lot of folks out there.
Simon C

 

[GorgesBoatworks]

Just want to say thank you for the information, I have a early 2000s Gehl 4635SXT with this same engine, nowhere in anything from Gehl is a thermostat mentioned. $61 and 10 minutes later, no more overheating!

 

[55chevydmax]

Just want to say thank you for the information, I have a early 2000s Gehl 4635SXT with this same engine, nowhere in anything from Gehl is a thermostat mentioned. $61 and 10 minutes later, no more overheating!

I have a 2000 gehl 4635, could you please tell me what thermostat to use. Thanks

 

[GorgesBoatworks]