Running Warm

[Gunslinger]

My 3a has a rebuilt motor with about 500 miles on it, so not quite broken in yet , but close.  In 70 degree temperatures it runs at a constant 170 degrees F, no problemo.  The last few days have been in the low 90s here and the temp will jump up to about 190, maybe a little less, but it seems to stay there.  Do I know the radiator is good, maybe.  I bought one used that had "little hours during restoration" on it.  Took it to a shop, they cleaned it and flushed it and said it had good flow.  I'm just curious what you guys are seeing for coolant temps in this hot weather.

Thanks

Todd

[JeepRoger]

Gunslinger, I have two CJ2As and live in California. When temperatures are in low 90's here, I see 180� rather often and a bit higher if the engine is working a bit (long but mile grades). One of my 2As runs a bit cooler than the other, and I attribute that to (probably) more residue in the engine's water jacket. ..R

[aboyandhisdog]

Gun,  mine runs at the same temps. as you have described.  175 is normal on the flats with usual summer temps here, but if the air temp is in the mid 80's and up, it will run hotter...190-195 especially if I'm pulling up a long gradual grade as JR describes.

One thing I did discover is that having a completely unrestricted air flow to the radiator is very helpful in keeping the temp down.  Clean those fins and remove the rock screen if you have one.

[Carls_jeep]

Question, are those that run hot have a bored out engine and what is the bore oversize?

[Gunslinger]

Mine is 60 over.
I'll try removing the rock screen this week and see what happens, I did retard the timing 5 degrees today and it seemed to help  We're headed for the Black Hills in a couple weeks and I want to make sure its good to go!!

[Carls_jeep]

Be sure to blow the radiator fins out from the fan side toward the grill.

[aboyandhisdog]

Gun,  one other thing you might check...is your radiator sealed well to the grill?  I just found that if there are gaps on one or more sides between the radiator and grill, your fan can't pull all of the air through the radiator first.  A lot of air will come to the fan AROUND the radiator and not THROUGH it.  They sell a kit for this made up of wide welting ($25 at Walcks) that you have to staple on, or you could do as I did and get a "rubber garage door bottom" strip at the hardware store.  

The one I got is made by MD #03723 and is 9 ft. long for $6.  Cut to fit and it is kind of a modified "L" shape so you can place it in several ways to find the best fit.  I used contact cement to adhere it to the grill and only needed it on the right side and along the top of the rad/grill.  It looks great - like it was just meant to be!  As far as I can tell, it has lowered my running temp by 5-10 degrees.  

[macrisel]

Sounds like a good idea.  Would you care to post of picture of this?

[Chasm]

If you have an original, correctly fitted fan shroud, you shouldn't have to worry about the space between the radiator and grill. The original fan fills the shroud and creates suction that pulls the outside air through the grill and back through the radiator. I really see the seal being a CJ2A issue as compared to the 3A. The side mount radiator set-up and shroud on a 3A are quite different from a 2A if you look at them side by side...

[aboyandhisdog]

You're right, Chasm - I have a bottom mount.
Mac, have been trying to post pics but am not having any luck at all.  Sorry.

[Gunslinger]

This is good stuff guys, thanks.  You probably remember that I just re-built the motor last summer, its got about 1000 miles on the new motor and latley its been running a little cooler, even on the hot days.  I was out just last night and put on about 40 miles, it was 80-85 F outside and the motor never got above that 185 or so mark.  So maybe its starting to loosen up.

I've been kind of worried because one of the problems I had last year was over heating on the second re-build, then after about 400 miles that build melted down as well and we started over.  I guess I'm starting to get some more confidence in the new motor.  I'll keep and eye on it, one of these days its got to cool down...Maybe.
Todd