Heater

[Ram50Man]

Hey does anyone have any idea why a heater would only blow out hot air when the RPM's are 2K or over? If its just at idle the air from the heater is luke warm at best. The thermostat is only about 2 months old, and its full on coolant.

[crvtec90]

Heater core might be plugged up and restricted. Get the engine up to temp and feel both of the hoses going in and out of it at the firewall and see if there is a big difference in temp. Careful...its hot! You can pull the hoses off and back flush it with a garden hose and see if a lot of crap comes out.

[pennyman1]

It could also be the vanes on the water pump have deteriorated and its not pushing water like it should. To really clean out the whole cooling system without hurting any parts is to drain out the coolant and run a mix of water and vinegar until hot, then drain and flush with water, then add the 50/50 coolant mix. The vinegar will dissolve the calcium buildup and any rust in the system with no damage to good parts. Also be sure the hoses are not collapsed inside - they can look and feel okay and be almost closed off inside.

[l.k.]

great info pennyman1...i will remember that for when i have to do mine

[Acuta73]

Get a T (backflushing kit, cheap!) fitting for the outlet line on the heater core, run vinegar or CLR or backflushing chemical in the system at operating temp for an hour-ish, let engine cool, open radiator cap, attach garden hose to back-flushing fitting, turn on water, start engine, run for 15-20 minutes, shut off engine, drain water, re-fill with coolant, ???, profit.

[mllrtm79]

Pennyman, how much would you dilute the vinegar to run through the cooling system? I am have a similar problem with my Ram this winter...

[92bluemax]

I worked at a tractor trailer shop and my boss had me drain a radiator on a freightliner and fill it with water and liquid tide and run it for two hours and then drain and fill with a 50/50 mix ! they never had problems with that truck overheating again:clap:

[pennyman1]

I have also read in Street Rodder to use Dawn dishwashing liquid - add it to the rad with the anti freeze in it - then run it for an hour or more , then flush and refill. As for the vinegar, a quart bottle then fill with water should do the trick.

[mllrtm79]

Thanks guys, I'll give it a shot, see what happens... with the "colder" weather we're supposed to be getting the next couple weeks, I'd like to have a warm truck.

[92bluemax]

Heat:P is very good in the winter