Engine Running Hot

[JAllenWAG]

Before I did my rebuild and all the upgrades below the engine stayed right at the top line of the blue on the guage. Now it runs up to about 215 and is getting up towards 220 now that the weather is warming up. I know an overbore will cause it to run warmer and mine is bored 30 over. I'm going to replace the t-stat with a 180 degree but other than that which cooling upgrades to you recommend? I've thought about the radiator, water pump, or adding an oil cooler. I'm kind of on a tight budget right now so I'm trying to figure out which one would help me the most.

[89grand]

The fan clutch is the usual (but often over looked) item when it comes to sudden over heating problems. Mine used to overheat too. I changed the thermostat and the radiator but it didn't help so I changed the fan clutch and all is good now. BTW I run a 180 degree thermostat also.

[ May 12, 2003, 11:58 AM: Message edited by: 89grand ]

[JAllenWAG]

Yeah I replaced the fan clutch and it helped some. Before changing it I was inching up towards the red when the weather got above 90. It isn't a sudden problem. It just started after rebuild that included all the upgrades I have listed. I'm guessing the overbore is the main cause of running hotter.

[Atlanta Wag]

Mine used to run hot especially in traffic. Since my AC did not work I pulled out the AC radiator thing now the temp gage never gets close to the middle position.

[Serious Johnson]

Jas':

Since it's now running hotter than before, we can reasonably ignore cooling system issues. Though an overbore and power increasing mods will add to cooling load, it shouldn't be enough to make a big difference to a properly functioning OEM cooling system.

Most likely, you have a problem with fuel mixture and/or ignition advance. In either case, a careful look at the plugs should indicate the required course of action. Another possibility is that your cooling system is marginal due to inadequate maintainence, and restoring power pushed it over the edge.

Fans only enhance cooling in very low speed situations like city traffic or low-range 'froaing, though a non-functioning fan clutch can impede flow a tiny bit at high speed.

Thermostats control how quickly a motor reaches running temperature, but do little beyond that unless they're broken. If your motor continues at speed to heat beyond the setting of your thermostat, then a different thermostat will only change how quickly it warms, and not it's ultimate temperature.

Generally, overheating at speed is an issue of inadequate cooling capacity. On a rig as close to stock as yours, unless mixture or timing are way off, this almost always means that the system is not up to snuff due to clogging.

:-

[Don S]

..
JAllenWAG...
...I Have a .o3o over bored 401 and am running a 190 'stat. Mine is running very cool because of the mods from the link below. My radiator is the original
Below is a link with a good overview of the whole overheating problem.
link>OVERHEATING & AIRFLOW 101 (http://groups.msn.com/JEEPTECH101/jeeptech.msnw)

Good Luck.. ;) and hope to CUL
Don S..

[JAllenWAG]

Don,

That's a great post. I have read it several times. I am having vapor lock problems as well. It's even worse now that the temp is starting to climb. I'm gonna go through the link more carefully and check everything. I just graduated college and finally have some money to fix all the problems I've been having for years! I know that the spring in my lower radiator hose is missing. Can this have much of an effect on cooling? The hose doesn't seem to be collapsed at all.

[maxrad]

JAllenWAG,

Serious and Don S are correct! I have also fixed most of these probs too. Another help could be the addition of a stock air dam rubber strip and a tranny cooler (Ipulled mine used from a yard for a few bucks).

[JAllenWAG]

maxrad-
I have a tranny cooler...PO had it put on as an option when he bought it. How much difference does an oil cooler make?

serious-
I also think it is a fuel/air ratio problem and possibly clogged radiator. I'm gonna get the calibrating kit and mess around with the carb. I have messed with the timing a lot and it hasn't made much difference. Right now I have it set at about 9 btdc. I just put new plugs in a couple months ago and they are already a greyish-white color. This indicates a lean mixture doesn't it?

[Matthew W. Woodruff]

What's with this "spring in the hose"?

Is it part of the hose itself or is it a separate part? I was having some overheating problems and bought some replacement hoses, but the problem fixed itself (at least for now).

Do I need this spring?

[JAllenWAG]

It's just a spring that goes inside the lower hose to keep it from collapsing. I'm not sure how important it is but mine was so nasty when I did the rebuild that I threw it away.

[Kukur]

A buddy and I were talking tranny coolers last night... trying to think of some ways to pull down the temp in mine.

Are there after-market kits available? Or am I going to have to take my woman to a junkyard for a picnic?

[JAllenWAG]

They are available from jeg's, summit, 4wd hardware...whichever company you prefer. Most of them are universal I believe (don't have any p/n's now). Of course a trip to the junkyard is always more fun and you save a lot of money.

[Kukur]

Thanks Jason!

If I go to the local yards, would I be looking to rip on out of another Jeep... or look for anything that has a cooler? Not sure if this was an option on the Wagon/Chero back in the day.

[JAllenWAG]

I am not sure what years have the cooler as an option. I am assuming most of the late 80's models had it as an option.

[Kukur]

Will keep my eyes out.

4wd.com has a one for $20

http://4wd.com/Shop4wd/ProductDetail.asp?ProductSku=3812

How much cooler should the girl run with a tranny cooler and a new radiator (2 or 3 core) without the cooler lines?

Guess I just want to make sure it will be beneficial for the time and $. (Just humor me and let me be able to tell my woman that it will make a HUGE difference smile.gif )

[Kukur]

Will keep my eyes out.

4wd.com has a one for $20

http://4wd.com/Shop4wd/ProductDetail.asp?ProductSku=3812

How much cooler should the girl run with a tranny cooler and a new radiator (2 or 3 core) without the cooler lines?

Guess I just want to make sure it will be beneficial for the time and $. (Just humor me and let me be able to tell my woman that it will make a HUGE difference smile.gif )

[JAllenWAG]

I honestly can't tell you how much difference it will make. I have a tranny cooler and have never had any trouble or rebuild on my transmission and it's at 190000 miles. I am in the process of researching a new 3 or 4 core radiator as well.

[Cliff]

Cooling suggestions:

Buy the biggest tranny cooler you can fit

Buy a mechanical temp gauge - I have seen more than one "overheating" caused by a bad temp gauge or sending unit.

The "gradual" nature of the problem leads me to the radiator. Do a flush, or better, have it rodded.

[Kukur]

Thanks Jason.

I think that is the direction I want to go.

Do you have A/C in yours? I have the AC condensor in front of the radiator now... I guess having the cooler below that wouldn't hurt.