Too HOT Hot Hot!!!

[Dirtweazle]

Got my 4.6 run around the neighborhood for a 300 mile brake in all last week. Took it out to the next town today. Freeway running on flat was fine about 218 to 222 or so. Around town from 210 to 222 and its happy. Once I hit hills on the freeway it would go over the 222 mark and instantly peg to overheat in red. Too quick to be accurate. Pull over and shut down. Overflow tank would proceed to piss most out. Refill and crank a bit till cool enough and refill all over again till I got home. Need help. Thinking its radiator problems. It is stock with around 130K on it. Everything else is new. I may be getting a little pinging with 89 gas. Getting some random valve noise im not used to the 4.0 didn't have. I also am working the engine a little harder running 32" tires with stock gearing. What would be the easiest fix first? Do I need different plugs? If radiator I need one for a 2K. Any one got numbers and location for a 3 core all metal?

Specs as follows:
2k XJ auto
2K block (Not sure if machinist took off requested .030) deck height at .049
95 stock cam (my 2k was shot, bearings toast and could not find another) Was told ODB1 cam was best for stock stroker builds..
new cam gear and chain set
91 head port and polish (had about .020 taken off to increase CR)( Have .030 spacers on rockers to comp. diff)
.051 head gasket.
Silvolite 19 cc dished pistons +.030
stock 2k intake and stock injectors match ported to head
Bored 60mm TB and cRusty intake K&N
stock 91 exhaust header match ported to head
2.5 exhaust all way out with HF cat and flowmaster
Melling HV oil pump.
bored water neck
new HV water pump


Next things on the shopping list are (in order) wideband AF computer, 4.56 gearing, 24 lbs injectors. These will have some affect on the heat but i am wondering if I need a new radiator to place at the front of the line?

-Troy

[SilverXJ]

Who makes you HV water pump?

I had a similar problem as you... over heating on the highway. Tried changing the rad, various t-stats. Finally removed the highflow water pump, replaced with standard and problem went away.

Or you could try this: http://www.go.jeep-xj.info/HowtoRadiatorRestrictor.htm

[Muad'Dib]

If radiator I need one for a 2K. Any one got numbers and location for a 3 core all metal?

FWIW here is a good rule of thumb for a radiator in our Jeeps:

Do you drive fast alot and barely 4 wheel? Go 3 core.

Want to wheel alot (or drive slow)? Go with a 2 core.

[Dirtweazle]

For San Diego I drive slow.. Keep it at 65 to get the best gas milage. Normal is 75 to 80. It is an everyday driver about to do 120 miles a day round trip. Like i said i will be regearing it soon to 4.56.. Because on the hills to work I need to DS out of OD and hitting 3k now, 2k in OD but no power. Overworking the motor.. Plan to froad it more once I can run it without HOT fear.

Recommend 2 or 3 for my application?

-Troy

[SilverXJ]

I recommend you try to find the cause instead of throwing parts at it. At highways speeds the high flow pump is pushing water through the rad too fast, not allowing for ample time for heat transfer. Or you could replace it with a new rad and come back when your problem is still there.

[Muad'Dib]

SilverXJ is right, the water pump is probably the culprit in your situation.

As far as how many cores i would suggest when it comes time to replace your radiator.

Go with a 2 core.

[Mgardiner1]

I recommend you try to find the cause instead of throwing parts at it. At highways speeds the high flow pump is pushing water through the rad too fast, not allowing for ample time for heat transfer. Or you could replace it with a new rad and come back when your problem is still there.

I have to disagree. I have a HV water pump on the front of my motor, and it runs cool as can be. The only issue i have is a cheapo thermostat. I say that because the temp will climb to 220, then the thermo opens and the needle rushes back down to proper temp. The T-stat only does that once on initial warm up cycle, then it regulates normally.

Are you absolutely sure you have all the air bled out of the cooling system? These engines can be a whore to bleed all the air out. My stroker also had a tendancy to push hotter temps on the highway for the first 1000 miles while breaking in. My gas mileage has increased by 3 mpg and temps run normal ALL the time now with about 2000 miles on it.

I'd look for other causes. Are your fans working correctly?

EDIT: this is the pump i have http://store.summitracing.com/partdetai ... toview=sku

[SilverXJ]

What does the impeller look like on that one?

You also have a YJ, which has a different radiator.

I am speaking from my experience. I had the exact problem this guy has. Ok around town, but got hot on the highway under load, pushing rpms. Usually with a clogged rad you would have hot all around. I had a high flow water pump, highflow t-stat, high flow t-stat housing. I went with a GDI rad because that was the only thing that wasn't replaced. Replaced it and no change. Replaced the water pump and the temps dropped to where they should be. I still would like to go back and try the restrictor mod eventually though.

[Mgardiner1]

couldn't you have asked me BEFORE i built the engine???

[SilverXJ]

couldn't you have asked me BEFORE i built the engine???

Ummm.. no... you need to go out there right now and take the pump off to take a look at the impeller.. must I do everything myself? Do you remember there being a plate on the back of it?

[Mgardiner1]

Yes, there was definitly a plate/diffuser on it. In fact i had to grind down a little bit of it because it was not welded on perfectly centered, and it contacted the engine block a little when i tried installing it

[SilverXJ]

There is something that I don't see in your list there too, weazle... I don't see any kind of fuel flow mods. Do you have any sort of piggy back computer or larger injectors?

[Mgardiner1]

Next things on the shopping list are (in order) wideband AF computer, 4.56 gearing, 24 lbs injectors. These will have some affect on the heat but i am wondering if I need a new radiator to place at the front of the line?

-Troy

Even if it was running lean enough to ping, i can't see the temp jumping as violently as he explained. However on the highway it will DEFINITELY cause things to get hot........

[SilverXJ]

I've seen a 4.6L run lean with out pinging.

[Dirtweazle]

This is why im going with the AF comp first to find out where im at on the mix. Dino's budget recipe says not mandatory on injectors so those got bumped lower on list. I did the restrictor plate mod but tow truck came and picked up the beast to take it back to the alignment shop. He says tierod is stripped out and will charge me $100 for a new one realign for free.. I think NOT!! Got a cRusty's tierod kit on order for that much. Should be here in few days. He will install and realign for no charge. Will test the restrictor plate then. Will also pick up my buddies coolant pump to check that.. How do I verify all air is out? Thermostat has small hole on top to burp. I do have the flush chingis on the heater core line. Plug in, turn on water with cap off and running?

BTW my water pump did not have the plate on the impeller. Looking back at receipts and its not a HV..