Strange engine overheating...on a V8?

[Oizarod115]

when you say overheat, what temperature does it get up to if left alone, will it get hot enough to pop the cap and boil over?

 

is it running 240* or staying around 220? or does it just climb until you stop it?

 

if the problem only comes at low speeds sounds like either water pump or fans is the problem, if she can consistently run 160 on the highway it almost sounds liek an airflow problem not waterflow problem,

 

if your a/c is INOP, try removing the a/c condenser, drilling two holes, and relocating the radiator about an inch or 2 forwards, this will gain room for some bigger/better fans you wanted.

[pilotblake]

when you say overheat, what temperature does it get up to if left alone, will it get hot enough to pop the cap and boil over?

 

is it running 240* or staying around 220? or does it just climb until you stop it?

It will keep going up. I have never let it get higher than 240. At 210-220 it starts idleing like crap, when I drive it, it is only short distances. I live in the country so a quick trip to town or out to the lake is about it.

 

if the problem only comes at low speeds sounds like either water pump or fans is the problem, if she can consistently run 160 on the highway it almost sounds liek an airflow problem not waterflow problem. I think airflow is one of the issues, but I would think on the trail with constant low speeds eventually all the airflow in the world won't be enough.

 

if your a/c is INOP, try removing the a/c condenser, drilling two holes, and relocating the radiator about an inch or 2 forwards, this will gain room for some bigger/better fans you wanted.It has already been moved up as far as I can get it to fit

 

Not sure why it says you got quoted Pete?

[streetjeep2.5]

Seeing small block chevys in XJ MJ engine compartments and the lack of any room for decent air flow has turned me off to putting one in my MJ. To me the few inches on either side of the heads, and that area take up by headers that give off lotsa heat, and the minimal space between the hood and engine, is a recipe, especially when driving slow in the summer, for overheating. My only thought is do some careful and nice cutting on the fender wells in the engine compartment and make for more air flow, put a hood that has a cowl induction scoop, functional of course, and try to have the radiator as far forward as possible to make room for fans.

[pilotblake]

Ill just take the hood off completely, I think I can get away with that here in my part of the world.

[Pete M]

might be worth a shot. :thumbsup:

 

if the problem only comes at low speeds sounds like either water pump or fans is the problem, if she can consistently run 160 on the highway it almost sounds liek an airflow problem not waterflow problem. I think airflow is one of the issues, but I would think on the trail with constant low speeds eventually all the airflow in the world won't be enough.

 

This may be as simple as your fans aren't strong enough. But there's only one way to find out for sure. You need more cfms. It's just a 305, not a built-up 400. You should be able to get enough cooling from a 4.0 sized radiator (and you do when more air is traveling past).

Also, make sure the hot air from inside the engine bay isn't recirculating to the front of the truck to get sucked back into the radiator. I remember the guys at extreme4x4 had that issue with a rear mounted rad on one of their projects.