[jm89]

Neither. T-stat hose rose by 2 degrees. The only gauge that fluctuates is the temp. I did get it up to near 210 on the gauge once, but I had to cover the radiator completely. Took over an hour at idle. As soon as I removed the cardboard, the needle almost immediately went back to it "normal" position.

 

[key99]

Neither. T-stat hose rose by 2 degrees. The only gauge that fluctuates is the temp. I did get it up to near 210 on the gauge once, but I had to cover the radiator completely. Took over an hour at idle. As soon as I removed the cardboard, the needle almost immediately went back to it "normal" position.

Rose 2 degrees to ?????? (whats the reading?)

If IR gun readings are stabil, maybe temp sender or connection/gauge is faulty.

... Could you hear blend door close?

 

[jm89]

Serving temps were nearly the same. T-stat housing hose temp was 167. With the cardboard it went up to 169. Blend door was completely closed. To the full heat position.

 

[jm89]

Okay. Let's just go from this.

Air blows warm at normal idle now, but blows hotter with raised RPM's. Possible causes?

 

[key99]

Serving temps were nearly the same. T-stat housing hose temp was 167. With the cardboard it went up to 169. Blend door was completely closed. To the full heat position.

With 195 stat, should read 195 ish (unless IR gun or reading is off).
... My 99 has 195 stat; my MiniTemp by Raytek gun reads 190+ just above clamp/stat (but it's a pain to get good readings on the buried Magnum hose).
... Have a small suspicion the Stant Superstat type stats are not helping, totally unsure though (no proof at all; and not gonna waste an nickel or minute to find out).

Air blows warm at normal idle now, but blows hotter with raised RPM's. Possible causes?

Has some htr core restriction (as said before, seems unless core is perfect/new there will be poor heater output at low RPM; your not alone, seems it's the bane of Magnum V8 owners that need decent heaters for colder climes). ... As ambients drop, your problem will worsen (depends what your willing to live with).
.. Helpful to mention your normal winter, and coldest winter ambients.
... When mode control is set to any "non recirculation" position, pretty darn sure yours will blow colder at higher/highest fan speeds (unless RPMs are high!).

... Earlier "bypass delete" link mentions the proposed "3/8" ish ID bushing/restricter mod"; spun360 installed a 1/4" ID bushing later in thread; you'll notice I'm a firm proponent the Magnums huge total bypass volume and chintzy water pump are the biggest cause of this all to common problem.

 

[Moparite]

Both lines to the core and from it are scalding hot. The mildly warm air is heater output.

Sorry if i missed something here but your issue is no/low heat? The above i think explains it all. Even if you flushed/reversed flushed the heater core it still can have a film that prevents heat transfer. The place i got my truck from got the truck with a leaking freeze plug, Instead of fixing it they poured in stop leak. As soon as i got it home the plugs where replaced and it was fully flushed. Worked well for the most part until a year or so later the temps would go way up in the summer heat and low/no heat in the winter. Long story short the radiator and the heater core had a build up of the crap on the inside preventing heat transfer. It sounds like this is your problem. I actually have replaced my heater core 3 times. First one clogged, Replacement started leaking and the third one is an aluminum one. So far the aluminum one works the best. I can start feeling some warmth coming out with only about 3-4 minuets of engine run time at 20-30 degree temps outside(with a 180 stat). Actually you can feel it before the gauge starts to move! It's only slight warmth but you can notice it. You are at full op temp and it's only warm. It's time for a heater core.

 

[jm89]

Think I finally got it. New thermostat. New thermostat housing(old one was warped a tad, not letting t-stat seat all the way. Put a mechanical gauge in place of the original. I will replace the original one in time. And placed a peice of cardboard over 2/3 of the radiator. Finally have heat blowing over 130 degrees in the cabin.

 

[jm89]

Moparite, I sure hope you're not correct, bit if the heat don't blow hot at 20 degree weather, that's all that's left. Also, I spoke to the previous owner and he said it had great heat in it until he changed the water pump on it. It was leaking from the weep hole he said. So that's a new water pump, radiator, and thermostat and housing. All that's left is the heater core.

 

[key99]

Think I finally got it. New thermostat. New thermostat housing(old one was warped a tad, not letting t-stat seat all the way. Put a mechanical gauge in place of the original. I will replace the original one in time. And placed a peice of cardboard over 2/3 of the radiator. Finally have heat blowing over 130 degrees in the cabin.

2/3rds is a lot for 40 ish ambient (don't think 01 sport has in rad/trough trans cooler, so it may be ok; mine has in rad cooler, at 2/3 would surely overheat when trans warms up on highway!!). ... Till you know how it behaves, would keep a close eye on that new gauge (less cardboard is likely safer

... With new stat and housing (195???), what IR readings do you get above the clamp/stat? ... at both core hoses? (again with fan and temp on high, widow open). ... Good to know to help others.

At least you've got enough heat now!!!

 

[key99]

Moparite, I sure hope you're not correct, bit if the heat don't blow hot at 20 degree weather, that's all that's left. Also, I spoke to the previous owner and he said it had great heat in it until he changed the water pump on it. It was leaking from the weep hole he said. So that's a new water pump, radiator, and thermostat and housing. All that's left is the heater core.

A work bud had same situation on a 95, good heat with original pump, terrible with a new (pump was changed in summer, didn't realize there was a problem till winter). ... Would have liked to see his old pump, but he threw it out.
... I've often wondered if there's different castings (or impellers), with the better ones compensating some for the huge volume bypassing; have looked into it in Chrysler parts books; found nothing, have no proof.
... I've learned to inspect ever new pump from now on for these engines, and to always keep the old pump.

 

[Moparite]

Seemed odd that both lines are about the same with the temp readings you posted. Glad to hear you got it figured out.

 

[jm89]

I asked him if he looked at them both to be sure, he said he didn't remember. Probably didn't. One thing I have learned with these magnum engines is to check and double check everything. Also, I'm thinking about changing the heater core just because my entire cooling system is new, so why not right. Researching the process now, I know the entire dash needs to come out. Looks about like a 6 hour process, or more.

 

[jm89]

Thanks moparite, it drove me insane trying to figure it out. But hopefully this is it.

 

[jm89]

Key99, my tuck does have a trans cooler in front of the rad. I want you all to know that I appreciate all the help. You guys have been very informational. Now hopefully the heat lasts. If not, the heater core will be replaced. And hopefully this isn't the last Ram I ever buy.

 

[key99]

my tuck does have a trans cooler in front of the rad.

hopefully the heat lasts. If not, the heater core will be replaced. And hopefully this isn't the last Ram I ever buy.

"Assuming" then it does not have exchanger in rad trough/tank for trans, so you won't have problems with cardboard as I do (it's a pain adjusting it to keep my keyster warm).

... Unless the core is real bad, at 20F amb the truck may not be instantly comfy, but ok (on the other hand, core is 14 yrs old, pinholes could be in the near future; my 99 has a pinhole, and pretty sure 97 is just now getting one too). ... My 97 engine warms up much much quicker than the 99, IDK why, but would sure like to know.
... I only say this as I refuse to keep changing effn cores without curing the root cause/causes of this widespread Magnum V8 problem (myself, betting heavily bypass restricter will improve flow thru any core and improve heat output, and keep new cores from going bad quickly).

... Ya, like 2G (especially QCab/sb setup, perfect for me); heaters, auto trans, and frt axle assembly dull the glow though.