jeeptester

I have a 4.8 2008 in a Jeep TJ. I have been running it about a year and 8000 miles. In the summer I have a hotter than normal issue at speed. 65 mph Hot day 208 deg to 210 flat road. at either higher speed of 75 or 80 mph or same speed just increased load of a long hill medium grade,

temps will climb to 216, or 218 deg If I let off and slow down it will go back to 210. (reading live data from scan tool)

Currently using the stock jeep bottle with small hose below cap,three core all Alu rad two speed fan 3500 cfm max fan w/shroud ,baffles at the top to force air from the front and not top or sides

I did some checking on the factory 2008 system that the engine came out of, and the recovery tank is tied into the heater hose and the plug 2/3 high on the rad (steam line connection point)

Will converting to this setup going to help , hurt, or make no diff ???

bczee

iTrader: (12)

What are the fan set to turn on/off for both low/high ? What T-Stat are you running ?

Have you check your tune for Fuel Ratio ?.. if your running lean or too much advance, that will also contribute to a hotter running engine.

But factory turn on E-Fan are set high, generally around these, Low = 220* and High = 237*. You have to remember that engine were design and set for Higher temp for emission reason. And from what your saying your running at, I would not be concern unless there seems to be a performance degrade or reason to be concern.

BC

jeeptester

Stock GM T-Stat and I had the fans set with a mech prob as the output from the ECU does not seem to work (I think ECU flash guy messed that up or something, so I just used external mech probe type) I had them coming on at 205 low and 210 high but just run high all the time in the summer.

So a 237 reading from the block via the scan tool isn't high? Wow I had no idea. (what is the max limit????)

I do see a degrade in power at the higher temp but Im thinking its because I have not finished building a box for the cold air intake and its just sucking the hot air from under the hood (at least that's my theory)
Oh and since this pic I have built a block at the top of the rad to force air from the front.

rotor vs. piston

iTrader: (3)

You should see the temp of whatever thermostat you have in, should be 190* if it's stock. So yes, 237* would be high. You likely need a shroud for your radiator or another way to make sure air doesn't go around it instead of through it, likely due to the awesome aerodynamics of a jeep at high speed

For instance I have a 190* 'stat in and at speed, usually anything about 30mph or more the computer reads pretty much 190.4 all the time. So far I've only done sustained driving up to 80mph and the temp is rock solid.

ls1nova71

iTrader: (4)

At highway speeds your electric fans are doing nothing for you, you need to make sure you have good ram airflow through the radiator, which means it needs to get in, but just as importantly, it needs to get back out. Really tight engine bays are bad about not allowing enough flow, and sometimes are made worse by the entire back side of the radiator being blocked by the electric fans.

CattleAc

iTrader: (7)

You don't have a big winch or other recovery gear in front of your radiator by any chance do you???

I've found this to be an issue more than once with "at speed cooling".

D_Eclipse9916

At speed cooling more has to do with ducting. Your fan does nothing at those speeds.

Make sure that there is plenty of clean air flow in front, and nothing hindering airflow through.

Airflow in front of radiator should build up in in a high pressure zone. Back of radiator should be low pressure to encourage airflow through the radiator. If there are huge holes allowing air to flow around the radiator, then you arent getting air through the radiator.

oange ss

iTrader: (50)

looks like you have plenty of airflow potential in, but need to address getting airflow out of the engine bay..and dump that aluminum intake tube and get the air filter out of the engine bay

jeeptester

Actually yes , I will take it off temp and see if it affects issue, and I agree this summer is worse than last and last summer I didn't have the winch

jeeptester

here is the fan shroud I built, I have since installed a faster 3500 cfm from summit slightly larger diameter but same basic shroud.

jeeptester

here is a shot of the front, you can see the trans cooler and the artic cat snow mobile hood vents I added

JIMB

iTrader: (2)

2001 LS6 in my 98 Wrangler.

195 stat for a little heat in the winter.

Novak LS swap radiator. No extra baffle around the radiator. No extra vents in the engine compartment.

Short tube to the right with K&N filter.

Not using the ECM to turn on the fan. Painless fan controller with sensor in lower tank of radiator to turn fan on and off.

Never gets above 210 at speed only during low speed traffic.

Using a Speedway motors recovery tanks. Heater hoses in the stock locations going to the water pump.

I'd confirm the tune.

rotor vs. piston

iTrader: (3)

wonder if it is indeed the winch... is it difficult to remove that for testing?

BLKMGK

Possible a hose is collapsing? How close is the fan to the radiator? Can you block off the area above the radiator to the core support so that air doesn't bypass the radiator altogether? Must the trans cooler be run blocking the radiator?

Overall you seem to have many things interfering with airflow including the fan shroud which seems to cover close to 1/3rd of your radiator. Could you take a drive with the fan assembly removed for testing at speed?

CattleAc

iTrader: (7)

I'll bet this will make a big difference at speed...

jeeptester

it does give a heater cir code for an o2 that dude said is deleted.

I guess this weekend I'll take the winch off and see, but Im still interested in getting that code gone. (GM dealer said the heater cir is no big deal, but it makes me think if he has that program error , what else did he miss)

any recommendations on a ecu guy?

jeeptester

I have thought about cutting some holes in the shroud,

Old Geezer

iTrader: (3)

That shroud pushed tite to the core is reducing the area that the air can flow thru. [Looks to me as tho the rad is now effectively the size of the fan.]
The shroud should be away from the core, so the fan[s] can pull air from the entire core face, and at hiway speeds allow free air flow.

jeeptester

yea Im thinking redesign is in order,

jeeptester

good news guys,

well I didn't think it would work, but I took the winch cover off and turned the control box to the side (it reduced height by about 5 inchs)

and even with today's OMG temps it ran at least 8 to 11 deg cooler, full load at speed never got over 205

I still need somebody's recommendation on a good programmer?