95cherokee89

I am having a bit of a problem with my 1988 XJ.
It is a renix, so you would probably know how inefficient the stock cooling system is...

Anyway, when I bought it, the P/O had bought a new radiator from grand cherokee I think is what he said but sold it to me before he installed it. After flushing the system and installing it, the vehicle never really over heats on the road, its off roading the thing just wont stay cool, it gets to the point where the computer kills the engine to prevent damage. I have replaced every component in the cooling system to no avail. My question is, is stock water pump be either A. dying, or B. not have a high enough flow rate for the radiator? would simply buying say, a hesco pump be enough? or is it something else all together?

Thanks for the help

Turbo X_J

You must be thinking of some other vehicle. If you let it get that freakin hot the first thing to do would be compression test to see if anything is left. If it's salvageable spend $200 to to replace the entire cooling system.

95cherokee89

Compression test came out at 150-160 on all cylinders. The thing runs fine, it just over heats off roading, really what I was asking is if there is a difference in the flow rate between a grand cherokee radiator and a renix one so I can decide which water pump to get

Even if it does end up blowing up, I have another engine I am rebuilding to put in, I just wanted to fix a few things with my current one till then ( gonna be a while till I swap)

RTorrez1

I can be that the fins ar gone on the water pump. Also when you changed the radiator did you change out the over looked fan clutch? A weak fan clutch will cause it to overheat at slow speeds.

Roler

Not so much the flow rate. However, there are some typical differences in causes related to when you overheat, in your case offroad/slow moving traffic.
Like Robert suggested: do not overlook the viscous fan clutch. If you dont know when it was replaced last, replace it now.

Overhauling your entire cooling system takes the guessing out of everything and can be done for a reasonable price.

95cherokee89

I don't *think* the fan clutch is bad, but its worth a shot, I have the electric fan wired up t0 a switch, so I keep it on when I'm offroading, I don't really need it at all when I'm on the road, its mostly just when I'm climbing a hill, or any situation when the engine is under load. normally I would just think its an xj thing, but two of my buddies have xjs doing the exact same stuff and never even get in the red.

Roler

Seems that could actually indicate your fan clutch is indeed under par...

RTorrez1

Everything you describe points to the fan clutch.

95cherokee89

you are most likely correct, I was doing some "in-town" driving, and the temps were indeed climbing under low speeds. I was thinking of doing a dual electric fan conversion, however I will need some kind of adjustable thermostatic switch to control the main fan

RTorrez1

If you do decided to put 2 elect fans make sure that the do put out enough CFM's (air flow) that is required. Or you will be overheating just as bad as you are now. Many of the off the shelf fans don't put out enough air flow to keep the 4.0 cool.

95cherokee89

I was thinking of installing a taurus fan, heard good things about them.
and either this:
or this: http://www.summitracing.com/int/part...6749/overview/

95cherokee89

I am having a bit of a problem here...

The vehicle has been acting a bit sluggish under certain circumstances, for instance, when taking off from a dead stop, it will bog down for about a second or so, and then recover, but have slightly reduced power. When I am cruising down the road, its perfectly fine, but sometimes it just feels... sluggish. would that indicate a bad fuel pump or pressure regulator? has a few months old fuel filter installed, no cat, and new injectors. I tested the pressure with a homemade pressure tester (just stuck a gauge onto a hose that screws onto the release port) and it read about 24-26 psi at idle, and about 28 at around 3k rpm, with the vacuum line on the regulator off, it was closer to 30/32psi. Now, the pump that's currently on there I got from an xj I bought for parts, no Idea how old it is, but it is definitely not stock.(I think its a walbro pump) it sounds a bit weak and slightly erratic, so its most likely going bad, but I just wanted to double check the symptoms first to make sure I'm buying the right part.