How does the coolant flow?

[RockyGryphon]

I'm guessing my flush knocked something loose and now its trapped in the radiator. Probably didn't help that I used some stop leak when a small hole opened up. Was your radiator replaced with an aluminum one by any chance?

I don't know what kind or how many cores it has, but I asked the mechanic to try to have it repaired before just replacing it and he said they attempted to but it kept falling apart. I know the left tank seam had separated from the frame which I repaired with steel epoxy and it survived about 900 miles, but after sitting for four years, it started leaking again when I started it back up. Nice thing about diesels, I don't think the fuel goes bad as easily as gas does. Though of course you can stabilize anything I suppose with the right stuff like Sta-Bil or whatever it's called. Supposedly you can even restore bad fuel with some solutions.

From a 6.2 manual I found on the internet:

"
GM 1825 M Spec. coolant is used in the 6.2L Diesel. It is a new specification with modified fomulations to lessen aluminum transport deposition (cavitation erosion). When engines with aluminum components are used with coolants not formuIated for aluminum, plugging of radiators and engine overheating has been observed. Aluminum cornpounds in the radiator tubes caused the plugging.

Both servlce and owners manuals call for GM 1825 M Spec. Coolant. The new coolant (1052753) conforms to GM 1825 M.
"

Dunno if this means to use orange or green coolant.

It's possible if you ever had hard water or there was some factory chemical in the coolant areas, they flaked off and came loose and may have blocked something. I suppose the other things that could cause overheating are:

Thermostat bad
Radiator fan clutch bad (quite possible after many years)
Water pump (if you have severe heat problems)
Belt!!!!!
Temperature sensor (not likely, double check with a ten dollar infra red thermometer from Harbor Freight or wherever).
Hose leak (if you're going to remove the coolant, good time to change the hoses).
gasket leaking exhaust into the coolant (I doubt it, but there's a chemical check for this to test your coolant for it).
Emergency brake on (yes seriously possible, feel sluggish?).
dirty old oil and filter?
Transmission fluid level low or dirty?
I don't know what else to guess at except what you said about some blockage. You could flush alternating directions to see if that clears it.

I would definitely recommend distilled water to mix with your coolant and not adding any leak chemicals unless you really want to.

 

[Milblazer]

Thermostat bad
Radiator fan clutch bad (quite possible after many years)
Water pump (if you have severe heat problems)
Belt!!!!!
Temperature sensor (not likely, double check with a ten dollar infra red thermometer from Harbor Freight or wherever).
Hose leak (if you're going to remove the coolant, good time to change the hoses).
gasket leaking exhaust into the coolant (I doubt it, but there's a chemical check for this to test your coolant for it).
Emergency brake on (yes seriously possible, feel sluggish?).
dirty old oil and filter?
Transmission fluid level low or dirty?
I don't know what else to guess at except what you said about some blockage. You could flush alternating directions to see if that clears it.

I would definitely recommend distilled water to mix with your coolant and not adding any leak chemicals unless you really want to.

The thermostat is new AC Delco
Fan clutch is good, no free spinning
Temp sensor is new (and i've used two different gauges just to be sure)
Hoses were replaced when I replaced the coolant.
When I flushed the radiator and motor I used the hose at first and then flushed with distilled water multiple times.
My bet is the water pump or a blockage. Since I have to dump the coolant again I'll be replacing the waterpump this time and converting to a serpentine setup. An oil change and transmission filter change will be on the menu too. Its going to be an expensive month

 

[RockyGryphon]

I guess filter the coolant you drain to see if you get debris and same with oil and trans fluid for metal, etc. Otherwise I don't know what to think of. I guess you could try putting a plumbing camera in the engine,etc.and risk getting that stuck and clogging things.

If you're changing the trans filter, check the pan for debris too wouldn't hurt I suppose. The only other possibility I could imagine might it be possible that fuel mixture could affect heat? If too rich, timing off, though I assume you'd see telltale sings in the exhaust at least wwhen starting cold.

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[RockyGryphon]

That rectangle fuel filter assembly can be problematic. I have heard of the heater element not working, dealt with o rings leaking, possibly get air leakage making for smoky starts, or not. Who knows. If it possibly affects fuel flow and heat I suppose it's something to consider as a wild guess to look at.

 

[rev3forme]

Did you ever figure out this out.I noticed this thread never found a solution, but I just installed an espar d5 and I'm having the same problem. Can you Explain how you routed the hoses and how it works please.

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[rev3forme]

RockyGryphon

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[skysurfer]

You won't get an answer from him, he hasn't checked in since March 2014.

 

[87scotty]

I've never had a winter front cause a diesel to get hot as long as temps are below 40 degrees they go on I think you may have other issues

 

[RockyGryphon]

Did you ever figure out this out.I noticed this thread never found a solution, but I just installed an espar d5 and I'm having the same problem. Can you Explain how you routed the hoses and how it works please.

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sorry it's been so long

I haven't installed yet but have found that according to the explanation in the online manual I found for the 6.2 diesel engine the flow of coolant goes from the engine to the heater core under the dashboard, then to the radiator, so unless you're willing to turn off the espar heater when you start, this won't work. I don't even know for sure if it'll work pushing it backwards into the engine this way.

I don't know which direction the coolant flows in the bypass hose, or even if it would flow when the water pump is off, but I guess I have to put a clear hose to see. Once I know the direction, I suppose I could attached the espar and see if coolant would actually flow with the engine water pump off too.

Anyone's ideas on this would be much appreciated.

 

[RockyGryphon]

well I think I've finally solved the problem. according to wikipedia anyway, "all" automobiles use centrifugal pumps for the water pump.

https://en.wikipedia.org/wiki/Radiator_(engine_cooling)#Coolant_pump

and looking at one of these,

https://en.wikipedia.org/wiki/Centrifugal_pump

https://en.wikipedia.org/wiki/File:Centrifugal_Pump.png

it appears that when stopped, there may be an open channel when the water pump is stopped. So my guess is that putting the espar output to the bypass hose into the water pump is the proper flow of coolant. then since the water pump pushes into the bottom of the block, it should heat up and return through the bypass to the espar and to the water pump. When the operating temperature is reached, the thermostat will open and take the coolant to the radiator, bypassing the espar unless you turn it on if needed while running and cold (suddenly going downhill in super cold temp).

If I get this installed and working, I'll post everything here. I've been getting a few parts ready before discovering my steering pump dries up every month or so and the hoses are all leaking or, splashing. that might have to come first.

 

[rev3forme]

I just installed an espar D5 to my 82 6.2 Diesel and after trying different ways ,I figured out the bast way I believe it to work.What I did is I teed into the line that runs from the rad to the heater core.You have to set up the d5 lower then the line to get the gravity suppy of coolant. I then took off the plate beside the vacuum pump on the right side opposite the glowplug control switch.You have to take out the vacuum pump to get the plate off.I tapped a 5/8 into 1/2 npt 90 degree fitting. I hope this helps.It works awesome for me.

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[rev3forme]

I use my truck for work and its 1500 km away from me right now.When I get back to it,I'll take pictures.

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[RockyGryphon]

Just curious, is that an opening to the water jacket?

 

[rev3forme]

That is correct Rocky.That's what I was told anyways. I couldn't find anything on coolant flow for the 6.2.My buddy had this set up ,That's how I found out about it.It works awesome.

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[RockyGryphon]

Just wondering, did you ever take a picture?