Hot, Hot, Hot

[rockman20]

Okay, we are seeing some mid 80's, low 90's here in the Dakotas and my truck is really starting to tick me off. I have a 93 one ton dually with the 454 under the hood and the 4l80 transmission. Here is my problem.

Truck will run right around the 210 mark during the highway. Off the highway it creeps to about 220. Idling and pulling a trailer full of hay, it will sit at a steady 250 all day long.

During this time the transmission will cook itself as well. Even on the highway it will just cook. (No trailer either)

Here is why this is ticking me off. I have had the radiator out and gone through and had a new side tank installed. I bought a transmission cooler that is rated for a 40,000 GVW. It is almost the size of the radiator in my Honda! (A little exaggeration, but not far off!) I have also installed a new thermostat as well. The fan clutch has no signs of leakage or anything. In fact, it looks damn near new. The shroud is all there. It is not broke, and the fan fills the entire opening and sticks out of the shroud just a bit.

Now, I did mount the cooler in front of the radiator. I could maybe see that causing the high engine temps. I had to mount it in front of that brace that runs down the center of the radiator. So there is about a 2" gap between the cooler and the radiator. I had to put it there because the cooler is too big to fit anywhere else. I am getting really ticked. I can't even pull a small 12 foot trailer without it cooking.

With it idling and being so hot that you can feel the water boiling in the upper radiator hose, the fan really doesn't seem to draw much air. It seems to blow a lot off the sides of the fan, but if you put your hand behind the fan, it doesn't feel like it is drawing a whole lot of air through.

Any suggestions? Could this be the sign of clogged exhaust? Bad CAT? Poor waterpump? Bad fan? Bad clutch? I need my dually! Please help!

Thanks!

[rockman20]

PS The gauge in the truck is slightly off. About 10 degrees. The gauge in the truck reads 210 but after a manual check of the coolant temp, I am seeing about 200. I have a 196 thermostat installed.

But the water will boil in the upper hose during these times.

Also, I have the transmission plumbed to go from the transmission, to the radiator, to the external cooler, back to the transmission. Not sure if it matters much, but I did mount the cooler so that the inlet and outlet are on the bottom of the cooler. I wanted it the other way so the oil would dump in, but I didn't have enough room on top before I hit the top of the core support.

[Tynee]

Starting with the basics, I'm sure you've checked the coolant level, is it staying steady, or are you having to add on a regular basis? If you're adding, tracking down the leak could very well solve your overheating issues. Are you absolutely certain that your radiator cap is in good shape? If it is worn out and allowing the pressure in the system to stay too low (or a leak is allowing the same), the coolant would be boiling at a lower temperature, and would not transfer as much heat out of the block as it should.

As a short-term fix, pull the T-stat and see if that helps. There are a lot of guys that will tell you not to run this way for extended periods of time, because the missing T-stat can actually allow the coolant to move through the radiator too quickly and not cool down to an acceptable temperature. I've never experienced this, but you should know its a possibility.

That's where I would start anyway. Also, you might pull the serpentine belt, grab a fan blade and see if you get any movement up and down. That's a sure sign of bad bearings in the water pump, and will tell you its definitely time to replace it.

Edit: There will be some other guys who can give you a better idea where the temp needle "should" run on your rig. I've never owned a big block.

[bodydropped]

like he said if u pull the t-stat i say cut the center out and use whats left in its place we use that on our dirt car since it restricts the flow some what but will slow down the water flow

[catch-22]

It sounds like your water pump might be going to me - just my .02

[bodydropped]

what size rad do u have and also what coolant mixture are u runnin

[piecesparts]

If the water is boiling, then maybe your radiator cap is bad. The principal of the cap is to raise pressure to the point that the water does not boil. At atmospheric pressure, water boils around 212 degrees, so this could be some of your problem.

The new T/stat could be a problem (new doesn't always mean it will work right) The T/stat could be sticking. I personally would run a 180 degree unit myself and then make sure you buy a "SUPERSTAT" style, to get the better modulation design.

The fan clutch is definitely a possibility, and a replacement is not an arm and a leg price--Might be a good thought.

I take it that the water pump has not been touched, but everything else has. If you have changed the belt lately---DID you get the belt installed right? Is it turning the fan and waterpump in the right direction. (MOST serpentine belt fans and waterpumps run counterclockwise) Take a look at the fan blades and see if they are turning the direction that they would pull air through the radiator. Your first statement was to the effect that the fan seemed like it wasn't moving much air. Check this out closely.

The mounting of the tranny cooler shouldn't cause you this much grief. I have mounted cooler on trucks without any impact to this extent. The one that you mounted is a big one though. If you are questioning this, take it back off and see if the problem goes away.

[rockman20]

The saga continues. Sorry it has taken so long to respond. Been a busy time with hay work, my normal work, and still trying to find time to work on my dually.

I have the tranny cooler off and I am going to run it like this to find out if that helps the engine temp.

The coolant is 50/50. Radiator cap is new. Water pump shows no signs of wiggle. Clutch has no signs of leaking and does not wobble and has slight resistance. Shroud is in good shape. Fan is rotating counter clockwise when you are looking at the truck from the front. It does pull air. It will suck a piece of paper up to the grill at an idle.

I am on the lookout for a 10 blade fan. Mine is only a 5. I figure this will help pull more air. I am also in the process of re-mounting my tranny cooler. I don't know how long it will last, but I am mounting it under the truck. Right up front. Under the front spoiler in between the frame crossmember and the bottom of the core support. I plan on making a steel cage to help try to protect it. I am also putting 2 small electric fans on it to help keep it cool and I may make a ram air setup through the front spoiler to help try to add more air flow.

Question on the transmission. It is the 4L80. The kit for the gauge told me to mount the sending unit in line with one of the cooler lines. I found a plug on the transmission that it fit into so I put it there. Is it possible that I am getting a hot reading because of this placement? The plug was on the drivers side.

Thanks for all the help! I will get this thing cooled. Now that I got the big tranny cooler off the front, I can now fit electric pusher fans up there. I am determined to stay cool!

[piecesparts]

That plug is the pressure line of the fluid that is fed to the tranny's in ternals. It is reading what you are actually running at inside the tranny, so it would be the most accurate temperature reading. This reading would also have the pump's internal heat included into it. The readings on the lines would be more of what the tranny sump would be at.

As for your overall cooling situation, if you are really serious about this radiator thing, I have a suggestion that would be to your benefit. The organization known as "Be Cool" radiators builds radiators that are guaranteed to lower your system's temps by 20 degrees. I have a couple of their aluminum radiators (one that is installed on my 84 GMC with a 383 stroker motor and electric fans and the other to be installed in a 68 Chvy truck project). I had the relay shut down on my fans one hot July day a couple years ago and the radiator handled the engine's temps without any hassle. I firmly believe in their product, even though it is pricey. I can go to a heavy traffic condition, which has a lot of stop and go times without boiling over. If I were you; I would talk to these guys, they can give you a lot of info on your problem and maybe some good answers Try them at www.becool.com ; and then call them.

[rockman20]

I'm no stranger to Be Cool. I have one of their full kits in my Oldsmobile. Radiator, cap, overflow can, and dual fans. I set my fans up to run seperately. The first one turns on around 198* This is the only fan that I can get to kick on. I have the other one set to 210* That one has only kicked on once and that was when I disabled the first one and ran the car for quite some time in the heat. But for over a grand, I better see some cooling.

I'm thinking about this route more and more. I will just need to come up with the cash. Thanks!!!!

[rockman20]

Update on the truck.

I tore the A/C condensor out this weekend. (A/C doesn't work anyways) Decided against mounting the cooler that close to the ground. The condensor looked good. It wasn't plugged, I could see through it, etc. But my god those things are huge! It is dang near the size of the radiator in my 69 Cutlass!

Removing that left lots of space for my transmission cooler. Got that all mounted up and decided to give it the test. It has been in the 90's and the 100's here for the past few days. I took the truck on a 150 mile adventure in 90 + degree weather. On the road, the transmission got about 170 the entire time. Engine stayed just around the 210* mark. That was for the first 75 miles. 75 miles was on the way back at which time I was towing a 4300 pound round baler back at 45 miles a hour. During this time the temp on the transmission creeped to 200 but would fluctuate between 190 and 200 the whole trip.

Another question. Does anyone know if I could buy a 10 blade fan for this application? Right now I have a 5 blade in there. I would suspect that a 10 would pull more air. I don't want to go with a flex fan, I would like to use the factory clutch setup, just would like more blades. Any ideas?

[piecesparts]

There are a lot of "flex" type fans with the factory clutch assemblies mounted to them. My 90 Chevy Silverado had a flex style fan blade setup with a T/stat clutch. I am not sure about a 10 blade fan for your vehicle, but I would give the guys at Flex-a-lite a call for a chance that they would have one. Summit Racing has some of their products in their catalog and they have heavy duty seven blade fans for more airflow.