Jeep Engine Heating Issue

[lupinsea]

I think I may have figured out why my engine was running on the warm side this last summer. . .

My water pump recently sprung a leak and in the process of fixing it I figured I'd pull the radiator, too, and give it a good cleaning out side of the rig. Turns out that was a good idea. The lower 1/4 of the vanes on the radiator were packed full of mud to the point I couldn't see any light through the fins. And on the front side was some odd collection of debris. And that was behind the "radiator" element for the A/C system (which I'll also be cleaning out).

The good news is that after 9 years the interior of the radiator, block, and rest of the cooling system is VERY clean. No nasty build-up.

The back side of the TJ's radiator.




Lower corner of the back side of the radiator.




Wad of debris on the front of the radiator (this was behind the A/C "radiator")




Oh, and a shot of the front of the engine, sans radiator and water pump.

.

[rumatt]

Hot damn! Impressive work getting it that dirty.

[John V]

That's about how the radiators on the Boxster looked when I cleaned them a couple summers ago. Completely filled with road grime, and almost entirely covered with bugs and leaves.

I was impressed that the car never ran hot.

[lupinsea]

Last summer my engine was running warm but the comment from my club was not to worry about it unless it stayed in the red on the temp guage as the archaic Jeep engines could take it. It at least got me through my summer fun, and fall fun, and some winter fun.

But it seemed like a good idea to clean out while the water pump was out.

I figured there would be some debris but I had no idea it was this clogged up. There were a lot of bird feathers in with the lump of debris on the front. As in, there might have been a bird that got sucked into the front grill area at one point. Spent a lot of time trying to back flush the crud out of the radiator. It only worked a little bit. Then I spent about an hour last night going tiny fin by tiny fin with a small flat bladed implement to dislodge the crud. I got about 1/3 of the radiator cleared out. Will work on the rest later as time permits.

[John V]

Simple green and a garden hose backflushing it worked for me. But mine was more "thick dust" than mud. A fine distinction to be sure.

[Rob]

A good example of a known fact in some circles - radiators are pretty much ridiculously over engineered for normal use.

[lupinsea]

Originally Posted by John V

Simple green and a garden hose backflushing it worked for me. But mine was more "thick dust" than mud. A fine distinction to be sure.

That had some effect but there is still a lot of crud jambed into the tiny openings. And this is more like caked on mud than simple dust.

Originally Posted by rob

A good example of a known fact in some circles - radiators are pretty much ridiculously over engineered for normal use.

Sort of like brake systems. For "normal" non-track, typical daily driving duties most brake systems are more than adequate. It's when you get into repeated high-speed braking like on a track that they start to fade.

With the Jeep on the trail average speeds are 3-5 mph with the t-case kicked into 4Lo and the engine ticking over about 1500 rpm +/-. Not exactly a high-effort situation. But the big expeditions I went on last summer were all in steep territory with LOTS of long, steep climbs.

I actually had more of a heat issue on the freeway than I did on the trails.

[lupinsea]

Got the Jeep put back together Saturday afternoon.

It took a lot longer than it should have but I was going slow, doing bits of the work at a time, and had a lot of other stuff crop up that required attention before the Jeep.

The radiator fins are now completely cleaned out.

And the A/C, um "radiator" (or heat exchanger?) that is in front of the radiator got cleaned out too. Blasted that from the back with compressed air. Holy cow, talk about turning the inside of the garage into a dust cloud.

Ended up needing to modify the fan shroud slightly. I noticed the fan blades had scraped gouge marks in the plastic. After installing a 1" body lift and a 1" motor-mount lift several years ago it looks like clearances were closer than I had realized and the fan (at some point) bit into the plastic. Using the dremel tool I elongated the screw holes in the shroud about 1/4" to lower the fan slightly. It should do the trick, only needed a little adjustment and it still forms a tight seal on the radiator.

During some long test driving where I was trying to get the engine to warm up I just couldn't. Won't know for certain until summer but I think I took care of my cooling issue. Engine was running a tick below the 210 mark on the thermostat (it's technically supposed to be right at 210) where as before I was runnig a couple needle widths above the 2010 mark (220 - 225 degrees), even i the colder winter temps (ambient air temp this weekend was 45 - 50 deg.).