nelson7172
NAXJA Forum User
- Location
- Villa Ridge, Mo.
A restricted exhaust system can also cause overheating.
Is it something other than the cooling system then? Perhaps the engine is not running correctly and causing an overheat?I have a completely new exhaust system connected to the stock manifold. It is the stock diameter, new CAT & muffler to the tail pipe... It is less than 4 months old & there is no damage to it.
So that can't be it.
are you running the shroud kits for the fans as well?
Everything has run great for months... recently I was traveling at 60 MPH up a steep hill, outdoor temp was 60ºF, & had the defroster on (means that the A/C was on), and it again spiked to 265ºF.
I turned off the defroster & turned on the heater to bring the temperature back down. It worked quickly...
This is what I have done so far to the cooling system:
High flow Mr. Gasket thermostat (stock temp)
High flow thermostat housing
Hi-Flow water pump
3 row aluminum radiator
New radiator cap
New upper & lower hoses
(3) electric fans with adjustable thermostat relay (set at 190ºF)
Added a hood air scoop (facing in reverse to create a negative pressure area in the engine compartment to increase air flow)
4 complete system flushes
New Heater Hoses
50/50 coolant
The electric fans are wired into the automatic relay, so that they are forced to come on with the A/C.
I have about 1000 lbs of gear on/in my 1999 XJ 4.0L A/T 4x4 (safari rack, after market bumpers, winch, rock sliders, a dead boar in cargo area, mother-in-law on roof, etc). The drivetrain is stock, OEM tires/wheels, w/a 3" lift. Lowered transfer case with SYE & new driveshaft.
Can anyone come up with a reason why this thing is still overheating??
I'm not sure what backflushing is either, but I had an overheating problem last summer. Changed out waterpump, t-stat, fan clutch, rad. cap...nothing worked. Then I burped the radiator and problem solved: Remove radiator cap (assuming open cooling system), turn on engine, watch for bubbles. For the first 30 to 45 minutes I just got a steady stream of tiny bubbles and then I got a sudden 3 inch drop in my fluid level...problem fixed, no more overheating. Call it vapor lock, gas bubble, trapped air, or whatever...the fix is easy and dirt cheap. Not sure its so easy with a closed system however.
I'm not sure what is meant by backflushing either, but I had an overheating problem last summer. Changed out waterpump, t-stat, fan clutch, rad. cap...nothing worked. Then I burped the radiator and problem solved: Remove radiator cap (assuming open cooling system), turn on engine, watch for bubbles. For the first 30 to 45 minutes I just got a steady stream of tiny bubbles and then I got a sudden 3 inch drop in my fluid level...problem fixed, no more overheating. Call it vapor lock, gas bubble, trapped air, or whatever...the fix is easy and dirt cheap. Not sure its so easy with a closed system however. It might help to point the vehicle uphill to facilitate movement of trapped air toward the radiator.
I have found that in an auto XJ, the transmission fluid transfers alot of heat back into the coolant when running up a steep hill. This can actually make the engine overheat because it counteracts the cooling being done by the radiator. It helps a great deal to use an auxilary (like a B&M) tranny cooler and don't run the tranny fluid through the radiator.