94 XJ overheating, help
 

Hello everyone, i am not new to cars or xj's for that matter. This vehicle in question is a 1994 cherokee sport, 5 speed manual 4.0 214k on the clock,. i am at wits end with this thing it has been a constant problem since 10k miles ago.. i have put over a grand in just parts. I am having issues overheating now but nothing else no sputters tap ticks or anything just overheating. Now to what all is new, ECU, all sensors on engine as well and tranny, yes all of them. fuel pump, distributor, valve cover, fuel injectors, exhaust from manifold to tail pipe, brand new. radiator, waterpump and 195 tstat and oil pump starter,,, the list goes on. also i have the rear of my hood lifted for extra ventilation. i just replaced the exhaust manifold due to a giant crack so i went ahead and did the whole exhaust, i cleaned all intake ports as well. now im overheating about 5 mins after its on im in the red, the top coolant hose is hot , WAY TO HOT and the bottom is like ice, which leads me to believe impeller issues waterpump or something. but i just replaced it not even a week ago. Guys i need your help any ideas??

also compression is great, and block tested, all cylinders within 10 psi

You didn't mention fans and fan clutch?

So what says it's overheating? Nothing will go thru the bottom hose 'til the stat opens.

sorry, also replaced fan clutch, DJB383 the dash gauge, i guess it could be false reading since i didnt see any boil over?

A motor just doesn't over heat in 5 mins. after start-up.......verify the goofy factory gauge.

X2. I would use even a cheap aftermarket gauge over the stock dash gauge. Also as djb383 said, its not going to over heat within 5 minutes of starting. You are lucky, or in a very hot climate if your T-Stat even opens that fast with a normal cooling system. You could probably remove the belt so the water pump isn't even turning and let it idle for quite awhile before it creeped out of the normal range.

Verify the actual temp first. Then go from there.

The first thing you need to do is verify you temp with a I.R. temp gun aimed at the t-stat house. Then you can go from there.

Yeah i understand, ill get a mechanical and throw on i think i got a spare from a derby car laying around. I just had a blond moment or something. Thanks i will let you all know.

alright so i verified, temp with my IR thermo, running at 205 solid so were good there i tried just cleaning contacts on the cluster unfortunately that was of no avail apparently now im below 260 within 30 seconds of start up, i had a couple extra water/oil gauges from some old derby cars but, they are WAY to big for this 94 xj is there a mechanical small enough? i have had no luck. Thanks guys

Most mechanical gauge sending units r huge compared to much smaller electrical gauge sending units. One is just as accurate as the other, according to AutoMeter.

yes but a new electrical gauge, anywhere but ebay etc... where it would be shipped is running around 100-180$ range cheapest being.... autozone which i hate and its some off brand for 70, i think im just going to get a sleeve for the rad hose and throw on the mechanical since im not all about spending a ton of money on something i can prob rig up. at least i know its not overheating now.

Locating the sending unit in the heater hose would be better......constant coolant flow the moment the motor starts thru the heater hose.......none to very little coolant flow thru the rad hose until the t-stat opens.

Here's an option......the 19mm sending unit/hose adapter will fit the XJ's 3/4" heater hose perfectly, and only $45, and digital display to boot.

http://www.trailtech.net/tto_temperature.html

Thank you, just ordered one. should be here Tuesday.