Well I just got this truck 94 ram 1500 with a 5.9L magnum and 56k original miles. and I've noticed the temp gauge acting weird. Usually it lays right at around 200. But when I start getting in the throttle hard and letting off it goes up to about 210 maby 215. I know this isn't much of a difference but I've never owned a vehicle that would increase temp that much everytime u get on it hard. I checked the coolant level its fine. When I first start driving in the morning I can hear the water pump moving the coolant. Which is also unusual for most cars I've owned. this a sign of air in the system? And will this cause this issue. Also I noticed the exhaust was replaced it seems to be kinda small for the motor size. I didn't know if maby it's too restricting or what's going on. And maby a new rad cap will help.. any help would be appriated

 

could be the thermostat was cooked at one time, and not working properly. you have more water than coolant in the system, clutch on the fan has gone on the fritz. Now after you stop romping on it does it cool back down or stay up around 210? the original T-stat is 200.

 

If you're hearing a gurgling or waterfall kind of noise, start the engine cold and put your head under the glove box while you rev the engine to about 2,000 RPM. If the noise is next to your head you've got air in the system. You can burp the system easily enough -- lots of threads about that in the forum. If the problem comes back a while later you've got a leak somewhere that's sucking air into the system during cool-down. Pinhole leaks that aren't big enough to result in coolant dripping on the ground are enough to do it, and can be really hard to find.

 

Yes it basically come from the heater core. It does sound like water fall. And will air in the system cause that to heat up.

 

So there ya have it. Now the fun part is figuring out where the leak is hiding.

Don't go romping on the thing until it's fixed. Cavitation and microboiling are not unheard of in these engines, especially with the stock 195 degree thermostat. You can't know whether or not they're happening until you tear the engine down -- last thing you want is to have the machine shop calling you to say that the magnaflux inspection went kaleidoscopic around cracked cylinder walls.

 

I tried burping it before I went to work. But nothing come out. It just kept pushing fluid into the overflow. I didn't let it get the whole way to 200. So I know the T stat didn't open yet. It was only 160. I didn't have enough time I had to leave for work. Does the T Stat have to open for this to properly burp?

 

Yes, it does. If you decide to change the 'stat, drill two 1/8th inch hole in it, so that there will always be some flow. Makes burping MUCH easier.

Also, the heater core is a real pain to get the air out of. it sits a bit higher than the radiator..... (which was a poor design decision.) Backflushing it, and then putting the hoses back together, while attempting to retain as much fluid as possible in it, is one way of dealing with it. Installing a 'flush T' RIGHT next to the heater core, on the outlet side, is another.

 

Yes . you want circulation to be happening , then top it up . If you can remove some before this process , you leave the cap off until full temp is reached and start adding coolant until full . If full from cold , it will over flow and get messy which is why I remove approx 1/4-1/2 gallon , then start . Never had an issue doing it this way for years .

I think 2damnyankee nailed it with the fan clutch being an issue . I get girgles in all mine "occasionally' but no temp issues . If it becomes an everyday thing , then you probably do have a leak somewhere .

 

Okay I burped the system. I got a decent amount of air out of the system. The clutch fan seems to be coming on and off fine. When it's cycling. But it stilled seems to be going around 210ish when I lay into the throttle a bit. But now it comes back down to under 200 when I'm gentle. Where exactly should the gauge be. I mean Is 210 or 215 too hot. Should i try a new t stat. If this isn't normal. Should I go with a lower t stat. Or stay stock

 

Stock stat is 195, and the gauge isn't the most accurate..... mine rides a hair above 200 under normal circumstances. I haven't noticed it changing much, no matter how hard I step on the Go pedal.

Wonder if you don't have a restriction in there somewhere? How does your coolant look? Any floaties in there??