What can I do to cool down my truck. I bought a 95 GMC 3500 dually 4x4 for towing my blazer to the trail. It has a custom air intake to the turbo that does not go to a box and 4 inch strait piped exhaust. I also has a manual boost controler that was already installed when I got it, but it does not seem to change anything when I adjust it. When I am empty or towing on level terrain, my engine temp is about 210 and my egt's are about 600. But when I go up a steep grade with a light load the egt's hit about 950-100 and the engine temp goes up slightly. If I have a heavy load,(my blazer and a load of wood for the weekend) the engine temp will hit about 250 and the egt's will hit 1100. The only thing I have been able to do to stop this so far is to slow down to about 30mph or just stop until evrything cools down. What can I do to lower these temps? I really am not worried about going fast, just getting there without overheating.
The engine temp problem can be fixed with a dual thermostat unit that GM started putting on the 6.5's in 98'. And a higher gpm water pump, the 98 water pump flows almost twice as much water. Around $150 from the dealer for the dual stat housing. About $70 for the water pump. The egts hitting 1100 is normal/fine. The manual boost control, my truck tows best at 10lbs of boost. I have had it to up to 15lbs. NOTE: 250* water temp on a stock 6.5 will blow the head gasket fast. 230* degree should be the back out temp. I have 92 6.5td and know this by experience. I made the mistake of going from 4.11 gears to 3.73 gears, great for fuel mileage, bad for towing. My truck liked the higher rpm for towing. Good Luck! WOODS
thanks for the info. When it started overheating I did not realise it until about 240 and then slowed down, but by the time I stopped it had actually briefly hit 255. I will definetly make those upgrades. probably needs a new radiator too. Everytime i go anywhere it leaks coolant off the front bumper, but none can be seen anywhere in the engine bay except at the bottom of the radiator, but this is a new developement. doesn't run any different or have water in the oil so I'm guessing (hoping) no blown head gasket.
Woods, on the swap you mentioned, is this a bolt in? It looks like it would be on the water pump, but looks like a lot of work on the thermostat housing.
swapping stuff Hey, while it looks strait forward, the water pump is not only attached from the front, but it also has ( if memory serves me right ) 6 or 8 bolts from behind the cover plate. So don't get confused if you undo the visible bolts and it don't break free. If I remember correctly again, the stock pump put out 78 GPM and the ones in 97 1/2 and later went to 130 GPM. The cross over pipe should only have the 4 bolts holding it to the block. But, I beleive you will need a new upper radiator hose. Otherwise, they both are relatively easy changes. If you only have $ for the pump, be very carefull about filling the system with new fluid, meaning on the stock thermostat housing, there should be a small brass screw/valve. Open it up and then add coolant. Don't know why, but on mine, it retained a small air pocket and messed with over heating and boiling of coolant out of truck. Open the valve and watch for coolant to seep out then close it. I don't know if the new housings have that valve or not. Hope this helps
Just remembered I almost forgot, SSDIESELSUPPLY.COM sells a ready to install kit to upgrade both those items and even throws in a new fan i think. Keep your cool ( sorry I just had to ) rotfl
thanks, I am just doing the water pump for now. But if it needs more afterwards I will swap the thermostat housing too. I'm actually swapping the water pump, putting on new hoses, radiator and deeper tranny pan and dif cover. doing it this weekend we'll see how it goes afterward.
cooling 2 I almost forgot (again)... You would be doing your self a great favor if before you start, you went to your gm dealer and bought a new thermostat. Its cheap insurance that your temp stays low and steady. Before I changed mine, it bounced around 185 ish up to 220 or so, depending on the day, load etc... and right up to the point of a rod knock noise (haven't pulled it apart yet) it barely moved over 190 ish after new stat. Good luck and don't forget to have a good gasket scraper and/or wire brush to really clean up the gasket surfaces.
Well, I replaced the radiator,hoses, thermostat and put on a water pump for a 98 and a mag-hytec tranny pan with synthetic fluid. The result is it still cruises about 210 but doesn't get any higher unless I manually drop it i to 3rd and accelerate up to about 3500 rpm's. I know I won't be rev it that high in normal operation, that was just while test driving it last night. got to say the synthetic tranny fluid seems to have made a big difference in acceleration and shifting. I was going to change to Mag-hytec dif cover also but didn't realize until I had the old cover off that they had sent me a metric cover and mine is standard. But, Oh well got the main things done.
dual thermostats congrats on the more steady temps. I think Woods is right about the dual thermostat housing. (aren't I nice at spending your $ ?) I would think that the new housing would open it up and let some water move. Picture it like this: a garden hose on a fire hydrant opened all the way will only allow so much water to move (even with a new pump), but now put a fire hose on it and watch out - your'e movin some water. What size radiator did you get? 3 or 4 core ? Hows the fan clutch ? Just throwin some ideas out Bummer bout the diff cover
I have a 14 bolt rear that is a standard design. the newer ones, according to mag-hytec evidently had a metric design. I recieved the metric on. It is not even close to fitting. I just didn't pay enough attention to it before actually starting to change them.
After a little further research with Jerry from Mag-Hytec we figured out that the distibutor sent an AA14 bolt cover not a GM14 bolt cover. Evidently the one was for a Dodge and sent on accident. The correct one is on the way though.
