hello. so im on my way to work. its 100degrees outside and my a/c is on and the engine temperature begins to climb past the halfway mark. luckily i was close to work so i park and turn off my a/c. slowly the engine temperature begins to return to normal. WHEW!!!!

on the way back home, the temperature outside is 63degrees. i drive with the a/c on the entire way and the engine temperature is normal throughout my trip.

ive recently replaced the waterpump. this never happened before i replaced the waterpump.

ive placed an order for a new fan clutch, thermostat, and drive belt. ill be installing them asap.

im just wondering, what is causing the engine to run hotter?????

would a loose drive belt cause overheating with the a/c on??????

 

Yes a loose belt can cause overheating, if the water pump is not turning fast enough it wont move coolant through the engine fast enough to cool it with the extra heat from the a/c.
The a/c condensor, that radiator in front of the engines radiator, takes all the heat from the a/c and dumps it in front of your radiator.
Are your electric fans working? They wont make any difference while driving but they do while stopped.
Next time it happens you can keep driving just turn the a/c off and then if it does not cool down in a mile or two then pull over and leave the engnine running but turn the heater to hot.
Engine cooling depends on air moving over the radiator.
A/c cooling depends on air moving over the condensor, thats why there are electric fans, when you are stopped there is no air moving over the condensor and your a/c would stop being cold in minutes.

 

Sounds like a bad radiator. How many miles? Any knowledge of having the radiator replaced/cored?

 

112000 on the clock. i have no idea when the rad was replaced.

i mentioned the loose belt thing because ever since i put it back on my tach has not been working when i turn on the engine. after a mile or so of driving it will start working. it hear squealing when the tach is not working.

i cant adjust belt tension right? so i may need to replace the belt tensioner and idler pulley??? and that may be why the engine is running hotter???

 

First, make sure your 2 electric fans are working when driving around town as well as with the a/c on.

 

No you can't adjust the tension. You'll need a new tensioner if the belt is squealing. I would replace the idler as well. Like Spike said if the belt is slipping it won't turn the water pump.

Like Mike says verify your electric fans come on when you use the a/c. If not I still think it's a bad a radiator.

 

Wish I had had this info earlier.
http://www.roverparts.com/TechTips/s...g_defender.cfm
If your belt is routed wrong your water pump will turn ini the wrong direction and your alternator wont work.
Check your belt routing.
If that is fine then you need a new belt tensioner.
The belt is slipping and not grabbing the pullies, once it gets hot it grabs the pullies and things start to work again.

 

thanks for the help!

belt routing is okay!

are the two electric fans in front of the rad? id go look for myself but its pretty late and dark out.

 

Yes the electric fans are in front of the radiator, you can see them if you look through the grill, they should be on whenever the a/c is on.
BUT...they do NOT cool the engine while you are moving, so if you are overheating while driving the electric fans are not your problem.

 

so the electric fans are working properly. i think the problem may be belt tension. im just waiting on these parts to arrive: drive belt, thermostat, fan clutch. anyone one why my tach is acting up?