The heat in my 2001 ram doesn't blow hot or even hardly warm . The temp gauge never hardly rose so I blocked the radiator with a peice of cardboard like in the old days and it still doesn't really get warm . The temp gauge never gets hardly over 150-175 , the top rad hose build up a lot of pressure though so I don't think it is thermostat .

 

Clogged heater core.

 

Could be a clogged heater core, but if the temp gauge isn't getting above 175, I would say the thermostat is at fault, meaning it's partially open which is preventing the engine from reaching its peak operating temperature. That would result in lukewarm heat from the HVAC system. I've seen this quite a few times.

 

Either that, or there simply isn't a thermostat in there.......

 

Funny you should say that. About 8 years ago, a lady I knew had a problem with her Mitsubish while on a trip to Florida. The car overheated (or was running hot) so she had a local mechanic (in Florida) repair her car. Well, he "repaired" it instead. About a month after returning, she complained to me that the temperature gauge needle would barely move and that the heater was weak. I pulled the t-stat housing to discover that the mechanic went to the trouble of breaking the pellet, spring, and supporting part of the housing off of the t-stat and reinstalling the base.

45 minutes of work and I had her good as new. I'm betting it's a t-stat in this instance as well. Chances are it's partially failing open, which is the desired effect.

 

When I bought my truck there was no thermostat in it. The PO had some overheating issues and couldn't figure out the problem(how they missed the huge hole in the upper radiator hose that was the problem is beyond me). Long story short, never saw temperatures over 150 and hardly any heat. Just my .02

 

Thanks , I thought at first maybe t-stat but wanted to get some opinions on it . I think I am going to pull it an give it the test on kitchen stove in boiling water and go ahead and do a complete flush on the system . It looks to be full of stop leak or something . thanks

 

If that's the case, I woud recommend a full flush, replacement of the heater core (if it hasn't been done), replacing the core plugs with brass plugs, replacement of the thermostat, and probably replacement of the radiator as well. Sounds like a lot, but better safe than sorry. Hell, throw in new heater hoses and a new water pump on top. Winter is coming, so why take the chance?

 

I never had heater in my truck. I decided to install a thermostat because the temp never was over 150 degrees and I thought the thermostat was removed (I owned a 1994 RAM in the past without Thermostat) but when I opened, noticed it was clogged but in the open position. When I installed the new one, heater inside cabin star to work. Good luck.

 

In reading the OP again, I'd replace the thermostat for sure and flush the heater core.