Proper operating temps of D7G?

[02Dmax]

Got a head scratcher. Customers 7G (92V) is running hot. I'm talking it'll get clear into the red just tracking down a road. We've replaced the thermostat, and water pump. We've removed the radiator and had it professionally cleaned. I've disassembled the heat exchangers and cleaned them. I've checked the fuel timing, I've ran the overhead. The radiator job seemed to help alot until the weather actually got hot.

In my opinion the gauge is slightly off but a laser temp gun is showing 208ish on the head. Oil cooler is 225. Trans cooler is 190.

Any ideas? Are these temps within spec?

Nige?

TCtractors?

 

[Bob/Ont]

What is the trans oil temp? You checked the fuel timing, has someone been working on it? Could it be timed up to #6 instead of #1?
Later Bob

 

[Nige]

Can't add anything much to what Bob's already posted. 1st question is has any work been done on the engine recently..?

Random thoughts
Is there any sort of shrouding around the radiator that could be missing thus reducing airflow over the core..?
You never mentioned fan or fan belt/tensioner condition. Could the fan be turning too slow..?

 

[R.D.G013]

Can't add anything much to what Bob's already posted. 1st question is has any work been done on the engine recently..?

Random thoughts
Is there any sort of shrouding around the radiator that could be missing thus reducing airflow over the core..?
You never mentioned fan or fan belt/tensioner condition. Could the fan be turning too slow..?

Don't know what sorta fan is on it but have seen a fan put on the wrong way round on a 25B that caused it to run hot, looked all right but just didn't cut the mustard in that it didn't move as much air as it would have had it ben on the right way, loose belts and worn pulleys would be another suspect.

 

[02Dmax]

Trans temp is between 185 and 190 where it comes into the heat exchanger. About 178-182ish where it comes out.

I put new belts on it just to cover my bases. I inspected the pulleys and they're all good. Fan is facing the right way and turning good. I haven't put a tachometer on the fan but it's moving a ton of air. All shrouds are in place.

No work has been done on the engine recently. It's got about 900 hrs on an overhaul and hasn't been touched since.

I assume that if everything is working like it should it should run right around 185?

I also replaced the dust sucker part of the pre cleaner because some of the tubes were melted and soot was plugging up the air filter. Really thought I had it whipped when I found that. The filter stays clean now but it didn't change the engine temp at all.

 

[Nige]

Might be worth a check of fan speed with a tach, just to rule it out.

Regarding the dust extractor, have you checked to see if it's sucking properly..? I''ve seen melted tube before caused by corrosion in the venturi inside the exhaust pipe that generates the "suck". If that's the case you'll have hot exhaust gas blowing into the air cleaner (that's what melts the tubes and coats the air filters in soot) instead of sucking and this will drastically increase your engine combustion (and hence coolant) temps.

Did the problem start suddenly or have the engine coolant temps been rising slowly over a period of time..? If they've been rising slowly maybe it could point to something from the overhaul.

Coolant temp I would say should run about 180-195 depending on the Part Number of the thermostat. Any idea what the Part Number is..? I can look it up.
What coolant is it using..?

 

[TXGOAT]

Is the cooling system pressure holding in the right range?

 

[02Dmax]

I can look up the ticket and see what thermostat I put in it. The problem originated this spring when it warmed up. We thought it was running a little warm in late winter but wasn't overheating. Once we cleaned the radiator core it cured it until temps got into the 80's. But now it's overheating even at 60 degrees.

I'll pull the muffler off and check out the venturi.

 

[Bob/Ont]

Trans temp is between 185 and 190 where it comes into the heat exchanger. About 178-182ish where it comes out.

I put new belts on it just to cover my bases. I inspected the pulleys and they're all good. Fan is facing the right way and turning good. I haven't put a tachometer on the fan but it's moving a ton of air. All shrouds are in place.

No work has been done on the engine recently. It's got about 900 hrs on an overhaul and hasn't been touched since.

I assume that if everything is working like it should it should run right around 185?

I also replaced the dust sucker part of the pre cleaner because some of the tubes were melted and soot was plugging up the air filter. Really thought I had it whipped when I found that. The filter stays clean now but it didn't change the engine temp at all.

You might have found something there. Take the hose off of the aspirator, hold your hand over it as you rev the engine. You need to feel a draw like a vacume cleaner. The draw is created by the venture and tube in the stack. The tube end must be positioned in the tear drops correctly to draw, if not hot exh will go into the intake. Any paper obstructing the top screen will cause the intake to draw exh into the intake. Waste machines have a check valve in the tube to prevent this.
Later Bob

 

[Delmer]

Completely out of left field, but is the oil level correct?

Also the temps of the hose going into the radiator, and the one coming back to the engine, and the air temp in front of the radiator, and behind the radiator might help.

 

[Mobiltech]

It seems strange that the engine oil cooler is at 225 and the head is only 208 and Trans 190. What is getting the engine oil so hot? What is the oil pressure running at. Is the coolant flow being restricted at the cooler.
Also temp drop across the rad would be good for know.

 

[Cmark]

Have you looked at the water pump? Early 3306s had a plastic impeller bonded to a metal hub and they would fail at the bond. In my experience, most of them have been replaced by now, but there's always a chance there's a few still out in the field.

 

[Nige]

CM, according to the OP he's replaced the water pump.

 

[Cmark]

CM, according to the OP he's replaced the water pump.

Oh yeh. Missed that. Cheers.

 

[Cmark]

You haven't perchance got a folded core radiator in this machine have you?

 

[Pathull]

we have a D7G (65V) I think is the same config as the 92v it has the folded core radiator in it, it would run hot after about an hour of operation, even walking the machine in second gear would get it hot, we replaced all the cores with genuine cat cores and it has run cool as since, its hard to get it to run any hotter then about 85 degrees C that's in the middle of summer in western NSW Australia where it isn't unusual for the temperature to reach 45 degrees C on a hot day. I would be making sure you only have about 7 or 8 degrees C of temperature drop over your radiator, (from top to bottom) anything more than that could indicate a restriction in your cores - lack of flow in your cooling system, or maybe take a coolant sample and send it to you local dealer your engine could be pressurizing the cooling system, cheers Pat

 

[nicky 68a]

Off base.....but has it had a new muffler fitted??

 

[Nige]

Off base.....but has it had a new muffler fitted??

Especially an aftermarket one that maybe does not have the correct venturi (or maybe no venturi at all) for the dust extractor system..?

 

[kshansen]

we have a D7G (65V) I think is the same config as the 92v it has the folded core radiator in it, it would run hot after about an hour of operation, even walking the machine in second gear would get it hot, we replaced all the cores with genuine cat cores and it has run cool as since, its hard to get it to run any hotter then about 85 degrees C that's in the middle of summer in western NSW Australia where it isn't unusual for the temperature to reach 45 degrees C on a hot day. I would be making sure you only have about 7 or 8 degrees C of temperature drop over your radiator, (from top to bottom) anything more than that could indicate a restriction in your cores - lack of flow in your cooling system, or maybe take a coolant sample and send it to you local dealer your engine could be pressurizing the cooling system, cheers Pat

The folded cores work good when new and kept very clean but once they got dirty they are about impossible to clean short of completely disassembling the radiator and then it was a chore to clean the outside 100% and if there was any build up on the inside of tubes inside forget it! Another of those designs that probably looked good on paper in a nice clean office. Designers need to spend a few years out in the "real world" before they are allowed to design anything!

 

[02Dmax]

It's got a standard radiator in it. Not the folded core type.

The water temp is dropping about 20 degrees from when it goes in the top of the radiator then back out the bottom. I'm not sure what spec is but 20 degrees seems like plenty.

Mobiltech I wondered the same thing about the engine oil and why it's getting so hot. Oil level is correct. The oil cooler is clean as a pin on both coolant, and oil sides of it.

I'm going to look into muffler situation more. I went back to look at it yesterday but when I got there they had another machine down that was higher priority than the 7. It does not have the check valve in the dust ejector tube and the precleaner I replaced was definitely melted. Which after input from you guys leads me to believe that the muffler is rotted internally. The air filter isn't coated in soot like it was but that doesn't mean hot exhaust isn't getting in.

Thanks for the ideas guys. I appreciate the pointers. I'll report back.