Too hot

[Stoy]

I have a 99 wrangler in Arizona 4 cyl. It starts to get hot when I am either idleing or going slow and have the A/C on. The radiator is new and also the thermistat is new! Any ideals? please help

[goodtimes]

Check the temperature drop across the radiator (inlet vs outlet). If you have a large temperature difference, then you are most likely not moving enough fluid at low RPM (bad waterpump, bad thermostat, or WRONG water pump)

....yes, I have had that problem in the past ....1991 I worked at a 4wd shop in Boulder CO, someone replaced their waterpump on a cherokee, but it didn't fix their problem, so they brought it to us. We eventually pulled the waterpump and noticed that the impeller was "backwards"....after investigating, we found out that CA emissions equipped vehicles had a different waterpump than the federal emissioins equipped vehicles....they turned opposite directions....not sure what years this applies to, but something for everyone to consider when replacing a water pump)....

If you don't have a considerable temperature drop (15 - 20 degrees), then you are either flowing too much fluid through the radiator, not moving enough air through it, or you have a bad radiator (not likely, and even less likely since you say it is new).

[USMC 0369]

Probably not relevant.

I'm sure my Jeep is in much more disrepair than is yours, but my problem was simply that the fan shroud was missing. I kept heating up (socal, mojave) when I'd idle or go slow and my buddy told me to get a fan shroud on there and it worked! Just my :2:

[Rawkon]

try a lower thermostat and make sure you coolant to water ratio is correct. 60 40 or 70 30 or buy premix

[avnative]

Check your clutch on the fan, It may not be locking up to allow the fan to pull the air thru like it should

If you are fine at higher speeds that shows all is doing its job, but at low speeds is where the fan really is needed, and if the clutch is not locking up then its not pulling the air thru it needs... Just my .02

[Stoy]

Ty

great advise thank you veery much

[paultyler]

Check your clutch on the fan, It may not be locking up to allow the fan to pull the air thru like it should

If you are fine at higher speeds that shows all is doing its job, but at low speeds is where the fan really is needed, and if the clutch is not locking up then its not pulling the air thru it needs... Just my .02

AVNATIVE is 100% right. That is your problem.

EDIT: Not that Avnative is right, but that your fan clutch is bad. LOL