96 ram 1500 318 heat trouble

i have problems with the heat in my truck. I have changed the following;

Clutch fan
Radiator
turpentine belt
Thermostat
Water pump.

all these parts were required, however....I still don't have very much heat in my truck....a mechanic said I need to check my head gasket and possible change it. I also heard it may be some vacuum hoses that control the heat. Anybody else have this problem? What can I do? Please help.

Have you flushed or replaced the heater core?

no. i havent replaced the heater core, but i have flushed it three times now, with the same result...water flows thru, and heat is given off...

i did check out the vacume hoses in the dash..and re-loobed the controls where the vacume lines attach..the heat seems to be staying on, however in extreme cold weather, not too much heat is given off.

are you loosing any anitfreeze? If your not then the head gasket to me can be ruled out.

i have problems with the heat in my truck. I have changed the following;

Clutch fan
Radiator
turpentine belt
Thermostat
Water pump.

all these parts were required, however....I still don't have very much heat in my truck....a mechanic said I need to check my head gasket and possible change it. I also heard it may be some vacuum hoses that control the heat. Anybody else have this problem? What can I do? Please help.

I wrote a posting not to long ago titled 99 Ram Heat Problem. I believe this is the same problem I have. Because of the reccommendations on my post, today I went out and bought some 7/32" vacuum hose and started replacing some vacuum lines. Believe it or not I have seen a difference but it hasn't cured my problem. I started with replacing the vacuum hose that connects right to the intake manifold. It did not have the tightest grip on the fitting so I started there. As soon as I replaced that 2" piece of hose I noticed that my controls started to act more immediate, as soon as I switched a position on my climate controls it reacted within a second. I also found that the check valve that connects to that 2" piece of hose was shot and I replaced that. Unfortunately I ran out of daylight so I could not change any more hose. I drove the truck later on this evening and found that the heat does seem to come out a little better but still seems like its a mix of hot air and cold air as I turn up the blower speed, almost as if a mixing door is not fully advanced. I will continue to replace hoses and fittings to see if there is any more improvements. I will keep updated.

i am not loosing any anti freez, and that is correct...my brother-in-law said it can't be the headgasget for that exact reason...(also no antifreeze in my oil). good to hear the vacumme hose check is working for some ppl..i checked mine this weekend, and it seems ok..and my heat is working kinda ok.

i am not loosing any anti freez, and that is correct...my brother-in-law said it can't be the headgasget for that exact reason...(also no antifreeze in my oil). good to hear the vacumme hose check is working for some ppl..i checked mine this weekend, and it seems ok..and my heat is working kinda ok.


What is the temperature of the new thermostat that you put in?

it is a winter thermostat. i think 195? but it is a winter one for sure

Could be the motor assembly that moves the hot/cold door in you ducts. Might be stalled in one position or bad.

Check out some more details on this other posting here:

http://www.automotiveforums.com/vbulletin/showthread.php?t=495681

Good Luck!!

thank you. i will check it out. but..i notice it is hotter when i leave it at a low fan setting...this could be due to the fact that it is warming up outside. :) i wont know until it gets cold again. thanks again. i will check that out too

hmmm. do you think i should check out the head gasget? i still have problems with the heat...a mechanic said there could be a leak in the head gasget and it is sucking air causing an air pocket in the heater core..could this be??? no anti-freeze in the oil to confirm a head gasget blown. what should i do?

personally I don't think it is a head gasket. one thing I can think of is have you had your fluids flushed lately? I have ehard of some peopel flushing their own fluids and get air bubbles in but if you get it done at a dealer or shop they do a good job. I like to flush my fluids about once a year soemtiems more. it depends on my driving and how much I offroad and get water in my system.
The 195 thermostat is the proper one that should be in. some people end up putting in 180s which don't work as well.

thank you

Ok, I am experiencing similar issues. I have a 98 Ram 318. I have had to change several parts on it. water pump, radiator, thermostat (4 times i have changed the thermostat). I have also flushed the system thoroughly and refilled with a 50/50 mix of antifreeze and deionized water. I have flushed the heater core thoroughly also. But my heat issue in the cab of the truck is directly related to my engine run temperature. During the summer it may come up to the range of 170 - 180 degrees. When it's about 30 degrees out it doesn't get above 140 - 150. I can do the cardboard trick and block a good portion of my radiator and get the engine temp to come up to the range of 200 - 210. And then my heat works great. I am now wondering if I could have an issue with my clutch fan engaging too much when it's running and causing the engine to not come up to temperature like it should. Has anyone else seen this? Thanks in advance.

forest, what does your temp guage read when your engine is warm? kyhillbillymonster, I've had problems with poor quality thermostats in the past. Did you get all the air out of the system when you did the work? Do you hear the fan clutch engaging a lot? On my truck you can mainly only hear it when the engine is cold.

jamesslcx, The thermostats I used were from a local mom and pop auto store here in town. Plus when I threw my arms up in the air and took it to a mechanic, he used a different supplier. I'm sure the thermostats are fine. I'm also very confident that I purged all the air out. Did it running. Jacked up the passenger side of the truck. Did it on an incline at the beginning of my driveway. All that stuff. The fan clutch. That's what's got me so puzzled. I don't hear it engaging from inside the truck. I'm not familiar enough with them to know what they should sound like. It's thermostatically controlled so I won't hear it like an electric one correct?
Thanks for replying.

Hey kyhillbillymonster, when the fan clutch engages you should be able to hear a roaring type noise from the engine compartment. I would say disable the fan and then drive it for a short distance but this would be a major pain on these trucks, your truck still has the fan shroud doesn't it?

jamesslcx, Yes it still has the shroud. How would I disable it? Unbolt it from the pully? I hadn't considered that.

Bad thing is you need special tools just to to remove or change the fan or clutch. Probably not your problem but have you replaced the radiator cap lately? When your engine is warm have you felt your upper and lower radiator hoses also your heater hoses? Both should be very warm or hot to the touch if not it could be a circulatory problem. Just a guess mind you but worth a check.

Yeah, i forgot to mentino a new cap was put on last year also.
I've checked all the circulation issues. Cleaned the entire system.
I bought a fan clutch this morning. We'll see if that fixes it.

Wasn't the fun clutch. Don't know what to do next. Very frustrating. At least I can use cardboard to stay warm this winter. Anyone else have this problem?

Turn the temperature knob from cold to hot & back to cold a few times in case the blend door is sticking.

Blend door isn't sticking. Thanks though.

Everything points towards the thermostadt. After driving how hot is your upper radiator hose? I believe you are dealing with 2 issues. The cold running engine and no heat in the cabin. Heater cores can be partially blocked where they do flush but transferring heat is no good. Do you know the temp rating of the thermo that the mech installed?

Yeah, I know. Everything does point to the thermostat. I'll have to take it out again and inspect it to see if there is something that keeps getting into there and holding it partially open or something. As far as heat goes in the cab of the truck. Once the engine comes up to temp. I get plenty of heat in the cab. It'll run you out it gets so hot. Thanks everyone for all the input.

Kyhillbillymonster, how long has your truck been doing this? Your engine temp should be at least 200 degrees when hot, strange problem. I had an older van with the same overcooling problem, I never could figure out why, I replaced everything cooling related but I never could get it right so I did the old cardboard trick like you did.

It's been going on for at least 3 years now. I am almost convinced that the coolant is somehow bypassing the thermostat and the engine is trying to heat all the coolant in the system. Which will never happen because it's being cooled in the radiator. Would like to take some time this weekend to investigate further. Has anyone ever heard of this happening?

It's been going on for at least 3 years now. I am almost convinced that the coolant is somehow bypassing the thermostat and the engine is trying to heat all the coolant in the system. Which will never happen because it's being cooled in the radiator. Would like to take some time this weekend to investigate further. Has anyone ever heard of this happening?

I've heard of improper gasket or wrong gasket install where the coolant flows around the thermo.

Two words: Blend Door. The plastic shaft that enters the blend door actuator distorts over time and gets sloppy, not allowing the blend door to fully shut off the intake for cold air. If you look under the passenger's side dash and watch the actuator turn as you reach up and turn the dial from cold to hot and vice versa. Look carefully and watch the white plastic portion of the actuator and the black plastic of the blend door shaft. If you see significant slop, that's your problem.

Blend door is fine for now. Thanks though. When I put cardboard in front of the radiator, I get heat.

So once it's warmed up, starting around your radiator. If you find areas of hot and cold then either "rod" your radiator or replace. Being a 96, I would replace.

"rod" the radiator? The radiator is practically new. Haven't had the time or funds to dive into this very deep. But I firmly believe that the coolant is bypassing the thermostat. I think there is a crack in the, forgive my ignorance, intake? Is that the part that the thermostat is mounted in? Anyways, when I get my tax return, I'll dive into it much deeper. Thanks again to everyone for the input. It is appreciated.