Over heating

[WarWagon]

I pulled the top of the fan shroud off so I could get between the condenser and the radiator. I used a shop vac to pull out about four hand fulls of bugs and stuff. Then I soaked the all the exchangers with a garden house and shot at a low psi - 60 I think - from the compressor nozzle. It was enough to blast water and bits and though I'm sure it didn't turn out as well as if I'd removed it, I do think I got it pretty clean.

This isn't going to do you much good. PERIOD!

You need to remove the grille and pull the oil cooler away from the condenser. Well documented mat will exist between them. Then pull the radiator to clean. Condenser can be cleaned in place with the radiator and oil cooler out of the way.

After doing that you can see by the additional junk removed why what you did isn't much.

 

[Acesneights1]

Yep, no cheating on this one.

 

[JiFaire]

I did mine your way, Dan ... I was stunned to find out how much I had missed.

Good thing I did it in the driveway, so I could wash the crap away; it was really amazing. Evey time I would spray, soak, and then wash it out again, I'd get MORE crap out of it...

Why do you think it took 3 hrs?

 

[Dan Hunter]

This isn't going to do you much good. PERIOD!

You need to remove the grille and pull the oil cooler away from the condenser. Well documented mat will exist between them. Then pull the radiator to clean. Condenser can be cleaned in place with the radiator and oil cooler out of the way.

After doing that you can see by the additional junk removed why what you did isn't much.

I did it in conjunction with my oil line/cooler install. Do I need to clean my brand new oil cooler? I'm inclined to believe that the crap in the shop vac and the crap lying on the driveway that dried and was swept up would indicate that my efforts had some effect. Also, it ran one index cooler after the cleaning. Moreover, though I did take about three hours of soaking and spraying mixed with other garage duties, I'm inclined to think doing this with some frequency is kind of like the oil change debate that continues on Harley forums; some would do anything to drain every last drop while some just accept that the oil is never really clean and just change it with some frequency.

I nonetheless accept my chastising.

 

[Rodd]

My truck is a 99. I was under the impression from other posts that the 99's had the bigger fan just like the dmax.

 

[JiFaire]

My truck is a 99. I was under the impression from other posts that the 99's had the bigger fan just like the dmax.

Some, not all. Count the blades... if it is a 9-blade metal fan, 20" dia, then yeah, it's the same as the 2000 , which is a good fan.

But some still had the 6-blade fan.

 

[buddy]

Is it a spin on fan clutch or bolt on to the water pump?

 

[Acesneights1]

I have the 9 blade with Hayden SD clutch. it works very good. And that is from someone who could have a truck overheat in Antartica...

 

[Rodd]

Some, not all. Count the blades... if it is a 9-blade metal fan, 20" dia, then yeah, it's the same as the 2000 , which is a good fan.

But some still had the 6-blade fan.

It's a 9 blade. I'll have to see what the diameter is. It looks like a 20 incher. I guess the rad is plugged and/or the fan clutch isn't working properly.

 

[Rodd]

Is it a spin on fan clutch or bolt on to the water pump?

It is a spin on.

 

[buddy]

So you got the latest factory GM cooling mod with what is apparantly the best flow balanced water pump and best fan they offered which started late in 1999. That is the spin on fan water pump set. For the time youd spend I would take the radaitor out and take it to a radiator shop and let them dip it and flush it in case there are some plugged veins.

 

[JiFaire]

You might have it hot-tanked once it's out, but I never bothered - it won't hurt, though. Cleaning the fins out and making sure that fan clutch is working would be my first priorities, if I were you.

Did you hear your fan kick in while you were overheating? The damn thing sounds like a turboprop when it engages, you can't miss it.

The clutch won't kick in if:

- the rad is too clogged to permit airflow (the hot air is what sets it off)
- the bimetal coil on the front of the clutch is dirty (same thing - dirt or oil will insulate the coil from heat)
- the fluid has leaked out (in which case the coil will be dirty)

They are a wear item... it's a fluid clutch, and over time, the fluid can leak out through the seals. Lots of people have trimmed the strip and re-set the geometry so it works again for a while, but it's a temporary fix. Might last 5 years, might last 6 months, might not work - depending on how bad the leak is.

There's a whole thread on this in the 6.5 Technical Library - Post #76 has a picture of a dirty bimetal coil.

 

[Rodd]

You might have it hot-tanked once it's out, but I never bothered - it won't hurt, though. Cleaning the fins out and making sure that fan clutch is working would be my first priorities, if I were you.

Did you hear your fan kick in while you were overheating? The damn thing sounds like a turboprop when it engages, you can't miss it.

The clutch won't kick in if:

- the rad is too clogged to permit airflow (the hot air is what sets it off)
- the bimetal coil on the front of the clutch is dirty (same thing - dirt or oil will insulate the coil from heat)
- the fluid has leaked out (in which case the coil will be dirty)

They are a wear item... it's a fluid clutch, and over time, the fluid can leak out through the seals. Lots of people have trimmed the strip and re-set the geometry so it works again for a while, but it's a temporary fix. Might last 5 years, might last 6 months, might not work - depending on how bad the leak is.

There's a whole thread on this in the 6.5 Technical Library - Post #76 has a picture of a dirty bimetal coil.

I went looking and I can't find post 76. I was looking at under radiator and cooling as well but didn't find anything. What heading is it under?

 

[JiFaire]

LOL ... sorry. Look under Fan Clutch Mod... Post #76 in that thread.

 

[WarWagon]

I did it in conjunction with my oil line/cooler install. Do I need to clean my brand new oil cooler?

My bad, I missed that you have pulled/changed the oil cooler.

The radiator really has to come out for the best cleaning. These systems were hard pressed to work under 215 when factory new and clean. I have already ate an engine over cooling so I may be a little to cranky. Oh well I can always be a bad example. ):h

 

[buddy]

The only reason I would have a radiator shop clean it is if you suspect it is plugged internally, because its going to be hard for you to flush it internally adequately.

 

[Rodd]

I was just looking at my fan seeing how to do the fan clutch mod and looked at the back of my radiator and saw a lot of the fins closed up. Maybe 10% of them. This is probably part of the problem.

 

[WarWagon]

I was just looking at my fan seeing how to do the fan clutch mod and looked at the back of my radiator and saw a lot of the fins closed up. Maybe 10% of them. This is probably part of the problem.

Someone attempted to air blast or pressure wash the radiator from the back side. Or dropped a fan or shroud during other work...

Original brass/copper radiator or a new plastic tank unit? Not sure if they had that on your year.

 

[Rodd]

Someone attempted to air blast or pressure wash the radiator from the back side. Or dropped a fan or shroud during other work...

Original brass/copper radiator or a new plastic tank unit? Not sure if they had that on your year.

The fill for the radiator is plastic up in the far corner by the air filter and A/C accumulator. The actual radiator is made of some sort of metal.

Looks like removing and cleaning is the next project. I think I read someones post earlier in this thread that they make a radiator comb to straighten the fins. Right?

 

[ak diesel driver]

you mean like this one?