Hi all,
how hot is too hot? My 2000 3500 5.9L got up to 224 today (according to the OBD tool) while idling with ac on at 95 degrees outside.

Is that too hot?

 

Hotter than I like to see, but, not yet "too hot".... but getting there.

 

I'd say it's pushing the limit. If this only happens at idle and not while driving, it could be the fan clutch is slipping and not pulling enough air through the radiator.

 

Thanks yall,

Any way to diagnose a fan clutch without just replacing it?

I do notice a different in temp between 55 and 75 mph. 55mph is actually cooler. I forget the exact measurements, but 55mph was 212 and 75 was 215 for example.

I also notice increasing idle rpm at stand still ( a little gas while in park) doesn’t help. To me that rules out water pump. Is that good logic?

I’m wondering if the radiator isn’t clogged. I know the antifreeze in it is good now, but with the cap removed the inside looks kinda funky. I’ll try to grab a pic.

 

I found another thread on there that seemed to describe my issue fairly well. He replaced radiator and it was all good. Maybe this is where I should go…
on my phone so I couldn’t link it, but it’s titled “

Fluctuating Temp Gauge.”

here is a pic inside the radiator cap:

 

I see some crusties, and restriction there..... I would suggest a flush, but, the flush chemicals today, are pretty useless.... and just don't do much in the way of cleaning. New radiators aren't too terrible expensive. If there is a radiator shop near you, having it boiled out would be another option.

 

@HeyYou , do I have to remove the radiator for the radiator shop to work on it?
Is that a pain since the transmission lines run through the radiator too? Do I have to basically dump all the transmission fluid and coolant, then pull the radiator, and refill?

Thanks,
Matt

 

You don't have to, can take them the whole truck, but, they are going to need it out of the truck, and will charge you to R&R the radiator.......

The quick connects, if you have the right tool, are easy. Still, its a radiator, and I think part of the design criteria is 'difficult to remove'.....

 

Maybe related... I just crawled under the van to verify that the trans lines go to the radiator as I thought I had a separate external trans cooler. I guess not.. but I noticed this fluid. It looks like its coming from the thermostat housing that I recently replaced. (side note, changing the thermostat is a super pain on this vehicle). I probably missed a bit of old gasket since I couldn't get eyes on the actual mating surface worth a crud.

It's barely leaking at all. I drove for over 300 miles in the last week and my reservoir is still mostly full. That wouldn't cause the temp to creep up, would it?

 

put a nascar radiator in it---jmmho