Hi all,

Yesterday I was towing my trailer (8000 #) over the Grapevine from Bakersfield to LA. (Big long steep hill for those of you not familiar with the Grapevine). It overheated. I had to keep the engine below 15000 rpms, A/C off and watch the temps the whole way. Occassionally I turned on the heat too. I don't have gauges. The dash oil gauge was fine, a bit above 40 but the water temp went WAY high. I had to pull over 2 times.

I wonder what you guys think the problem is. I have had mild temp elevation before on hot days. Yesterday was about 93.

My thoughts... Radiator needs service?
Water pump problem?
slipping belt?

Others??

Where would you start to troubleshoot or what would you guys do first?

Val

 

I would replace the thermostat first. It is cheap, cheaper than the other options, and easy to do. I would go with the 180* t-stat, instead of the 190*. I would also get it from a Cummins dealer instead of the Dodge dealer, unless you just like to pay the extra 100% mark-up.

 

Stupid question, but did you check the coolant level in the radiator?

I've run Grapevine with 1000# in the bed, turning my 37's with the A/C on. Even with outside temps over 100, I ran 75 MPH all the way over and never got over 190*.

Does your gauge needle fluctuate? Sometimes mine will drop suddenly and then creep up again. This is normal. If your fluid level is okay, I'd agree with firestorm. Start with the t-stat. Also check the front of your radiator, if it's boogered up with bugs and what not that will hurt airflow through the radiator.

Cooling system service would be a good idea while you're at it......

 

Check the fan clutch also. Where was your guage at? my 93 runs around 1/2 to 5/8 pullin hills with a 2k load in o/d on the grape vine at 65 or so.

 

Start by cleaning your radiator fins and the condenser and cooler these get plugged by buggs and dirt

What was the engine temp did it go over 220* if it did you could warp a head

You are running a 50/50 mix anti-frezze ??

As others have said it mite be your stat

 

I disagree with running a colder thermostat. The reason being, diesels love heat (within reason), and run more efficiently at 190* than at 180*.
JMHO...

 

thanks guys, I did have 50/50 mix and radiator well filled. It has a few bugs but is definitely not all goobered up. The cooling guys say the problem is that my radiator is bad, needs replacing. We discussed cleaning it and rodding it instead but they think it needs a new on. They also say it needs new clutch. I never heard it engage yesterday and that is unusual. Hope I'm not just getting taken, but the truck has had a history of heating up when towing up hills and I have ignored it for a year. Nothing like yesterday though... never above 220. I got to the red mark at 240 as I was pulling off the side of the road when I first noticed the problem. I looked down and said gee this is heating up just as the Check Gauges light came on. I stopped and idled and it cooled very quickly. I never let it get above 220 after that. I hope there is no damage... any way to check that?

NEW QUESTION: What brand of radiator should I buy. The guy wants to put in a GDI... any thoughts?

Thanks

 

Make sure your rad is clear, then I would change the fan clutch!
If you don't hear the fan coming on the ad is plugged or the fan clutch is toast, If you build engine temp ok on the gauge then thermo stat is probaly ok, it's just not giving up the heat at the rad, Do you run a bug front?

 

if you tow heavy and have a consistent problem with overheating i would get a cowl hood or drill large holes in the the cowl under the black plastic piece between hood and windshield. The cowl hood will make a dramatic difference. I've seen on 12V them run as much as 30-40 degrees cooler.

 

BigDog, I would be surprised and dismayed if your rad was plugged internally with corrosion in 3 years.

Do you still have the "blowby" bottle installed in original location? Move it or run some tubing as the blowby does plug up the external fin passages and restricts air flow. You may need to clean the external of the rad. It can be plugged and is very hard to see, use a light.

There is a rubber air dam at the bottom and in front of the rad and if it is dislodged it can allow air to divert around the rad and result in a lot less cooling at higher demand.

Viscous fan clutch probably a problem by your description.
IMHO, good luck.

 

What tranny do you have? If it's an auto, get a gauge. You may have over heated the tranny and scavenged heat from the cooler.

 

At work to check fan clutch operation I have a piece of card board that fits the front of the radiator on Dodge pickups. It slides down right in front of the rad. Hood shut I'll run the engine at 2500 rpms and wait. Generally a little past 190-210 (1/2 on the gauge, sometimes a little over) you will hear the roar of the fan kicking in.

 

Thanks for the tips guys. I went ahead and let the guy replace my fan clutch, rad and t-stat. I hope I wasn't just taken for a ride. Decided to do it since I have had minor overheat probs. with this truck since I got it a year ago. I don't have any idea how it was treated before I bought it or what it was used for.

I love the cardboard trick. Nice tip. I know my fan didn't kick on so am pretty sure that was a big part of the prob. They took the rad off and said it was all clogged up in the middle. They took a "gun" and read the internal water temp on one side of the rad compared to the other and got a 50* difference. That does sound pretty bad. After a minute or two of rest it was still 30* off.

 

As you said the fan clutch will make a big diff, at least on mine it did. Look at the good side, everything is new now so you have peice of mind, what the hey, its only $$ ,cant take it with you when you go., its also much cheaper than a new engine. BTW I have used a GoDanInd rad in my jeep and had no problems.

 

what the hey, its only $$ ,cant take it with you when you go., its also much cheaper than a new engine.


Good Point Apache!

If I never overheat... I'll be happy