[92blackcummins]

My radiator had a leak in it, so I pulled it out and had it welded up. The shop boiled it and cleaned it up too. They said they got a lot of junk out of it. The problem is, the heater used to blow so hot it would cook you out and now it is nowhere near as hot! I have never had to put cardboard in front of the radiator, but I covered about 2/3 of it today and it seemed to help a little, but it is not even close to how hot it used to blow... What do you guys think?
Just FYI... the high here today was 14 degrees and the low was about -6.

 

[9297oldram]

A clean or new radiator cools better.

 

[simplysmn]

Also check the valve on the heater hoses it may look like it's working and not be opening all the way up .

 

[mrmoparwl]

New thermostat in the last while or not??? Mine is apparently the second one in 460000km! :O

 

[fisrtgenlover]

Possible air in the system still??

 

[Shainer]

My radiator had a leak in it, so I pulled it out and had it welded up. The shop boiled it and cleaned it up too. They said they got a lot of junk out of it. The problem is, the heater used to blow so hot it would cook you out and now it is nowhere near as hot! I have never had to put cardboard in front of the radiator, but I covered about 2/3 of it today and it seemed to help a little, but it is not even close to how hot it used to blow... What do you guys think?
Just FYI... the high here today was 14 degrees and the low was about -6.

If they pulled a lot of crap out of it, your heater core is not too far behind it. Also if you never had to block the radiator, then your coolant temps were most certainly higher.