overheating

WolverineFW · **Posted:** Mon Jun 06, 2011 10:20 pm

Anyone with an overheating problem actually cleaned their radiator fins out from inside the engine bay out towards the front of the vehicle?

JL Rockies · **Posted:** Mon Jun 06, 2011 11:31 pm

Yeah... No.... No one thought to check that. I even removed the condensor to make sure there was nothing in between it and the radiator. Again, there are post that span years with no verified solutions. Buying the 4Runner was the only solution I have found over the last 3 yrs of KJ ownership. Excellent winter vehicle though.

DOC4444 · **Posted:** Mon Jun 06, 2011 11:40 pm

The fan clutch engagement is based on AIR TEMP, NOT coolant temp. In heavy hot weather towing up strong highway grades, the coolant temp rises so fast that air around the clutch lags behind. That's why even new OEMs that engage at 215 to 225 simply don't.

DOC

tjkj2002 · **Posted:** Mon Jun 06, 2011 11:50 pm

If you cleaned everything and replaced as many parts as you have there is still many factors that can lead to overheating.

The 1st one would be do you have the correct coolant in the system? Could be a cavitation issue which really hurts cooling.

2nd is airflow,gotta have airflow to cool and all that fancy stuff up front drastically reduces airflow.You got alot of coolers up front and that air get's plenty hot before it ever reaches the radiator.

Open up the hood and at the base of the windshield cowl is a rubber seal that seals up to the hood,remove that and try again.

DOC4444 · **Posted:** Tue Jun 07, 2011 8:09 am

BTW,

When we have seen the rapid rise of the (recalibrated) temp gauge literally to the peg while towing up a long highway grade in hot weather, we have never heard the warning chimes, nor the "roar" which presumably would occur if the fan clutch actually engaged. In each case when the gauge pegged, we have backed way off and the temp has come right down with no evidence that the new OEM fan clutch ever engaged. It is not clear whether any defueling occured, but I assume not, due to continued good performance and the lack of the warning chimes.

I am optimistic that the Hayden will be the solution to all this for most of us. I would only go to a fan that moves more air if the clutch clearly engages at an appropriate point and the temp still does not get fully back within bounds.

On our old '99 diesel Suburban, the similar OEM fan clutch DID engage, but did so too late in the process to be effective. Replacing with a Hayden with a lower cut-in temp got "ahead" of the problem, avoiding defueling and being unable to go more than 40 MPH with a trailer.

DOC

DOC4444 · **Posted:** Tue Jun 07, 2011 8:19 am

Wolverine,

Yes, I even used some trick radiator fin cleaner and flushed it out from the inside with first water and then compressed air.

DOC

Wobbly · **Posted:** Tue Jun 07, 2011 11:48 am

Some idle speculation: Is the CRD viscous fan clutch repairable? According to these links, some viscous fan clutches on Porsches have been rebuilt. Toyota sells silicone fluid in three viscosity ranges which would allow different fan performance. Not sure if the Jeep design uses a bimetallic strip like those shown in the links. If so, perhaps different activation temperature strips are available.

http://www.nichols.nu/tip482.htm
http://members.rennlist.com/blueshark/page11.html
http://www2.zhome.com:81/ZCMnL/tech/Fan ... Clutch.htm

JL Rockies · **Posted:** Tue Jun 07, 2011 12:51 pm

My summertime blues dates back before all the coolness I added up front (ARB, winch, winch controller). The first time I had to turn on the heat was July 2007, I had a special friend from FL visiting me and I took her out to Canyonlands for an easy trail ride. Since she's more of an indoor girl I had the windows up with the AC on because it was like 105 deg. On the way up Shaffer Trail I noticed that the temp gauge was climbing at about the same rate as the trail so I had to roll down the windows and turn on the heat. I didn't add front bumper coolness until late 2008. I'll try to remove the rear seal and see what happens.

The last trans flush was done by the dealer in Dec 2008 and I added the HOAT stuff to the tank to replace what was lost during the timing belt replacement in Feb 2011.

It might all be moot since I am working to put the vehicle back to stock and recon it for sale (all the cool pieces are presold). Pastafari was supposed to be my last trip with it but it looks like Beef Basin this weekend might be it. I might have to wait until the fall so all this hotness doesn't interfere with a test drive.

papaindigo · **Posted:** Tue Jun 07, 2011 1:26 pm

Wobbly they may be rebuildable but, as big a fan of rebuilding as I tend to be, is it worth the bother given the price of the much heavier duty Hayden clutch?

Wobbly · **Posted:** Tue Jun 07, 2011 3:06 pm

papaindigo wrote:

Wobbly they may be rebuildable but, as big a fan of rebuilding as I tend to be, is it worth the bother given the price of the much heavier duty Hayden clutch?

No, not worth rebuilding the the stock unit if the Hayden 2905 performs well. How has it performed?

papaindigo · **Posted:** Tue Jun 07, 2011 4:02 pm

I don't know from personal experience; I'm not having problems with overheating but thought I'd give Kap's fixed fan a try at which time I may throw a Hayden on my OEM fan just in case I or stoutdog need it.. I think TJ2 intalled one about a year ago.

Wobbly · **Posted:** Tue Jun 07, 2011 5:38 pm

Some interesting discussion towards the end of the thread about flex fans, also some tips on adjusting fan clutches for different engagement temperatures: http://yarchive.net/car/fan_clutch.html

ATXKJ · **Posted:** Tue Jun 07, 2011 7:39 pm

Wobbly - that threads from 1991 about a 77 280Z
I don't think you can adjust our fan clutches that way - ours are fluid filled not a spring

also back when Mark was working on the Fixed fan - I asked him about it flexing and he said it would flex - above the CRD's rpm range and that it was still curved at 'high' CRD speeds

I don't know - for a test - I'd use the stock fan and just get the spacer to replace the fan clutch - don't know that I'd want to run that way for long - the Fan clutch is a better idea - it just needs to work right, and because of the bad clutches that folks have found - I think that should be a main focus of an overheating investigation.

Wobbly · **Posted:** Tue Jun 07, 2011 8:51 pm

ATXKJ wrote:

Wobbly - that threads from 1991 about a 77 280Z
I don't think you can adjust our fan clutches that way - ours are fluid filled not a spring

also back when Mark was working on the Fixed fan - I asked him about it flexing and he said it would flex - above the CRD's rpm range and that it was still curved at 'high' CRD speeds

I don't know - for a test - I'd use the stock fan and just get the spacer to replace the fan clutch - don't know that I'd want to run that way for long - the Fan clutch is a better idea - it just needs to work right, and because of the bad clutches that folks have found - I think that should be a main focus of an overheating investigation.

The Datsun fan clutch being discussed is also filled with fluid, although it's not silicone, and has a helical thermostatic spring which operates a valve. I've never had a good look at the stock CRD fan clutch to see whether it has a thermostatic valve.

Flexing above the CRD's range makes sense if the flex fan's primary application is for higher revving gasoline engines.

Wobbly · **Posted:** Wed Jun 08, 2011 12:01 pm

More idle speculation: Borg Warner makes a 'Vistronic' pulse width modulation fan clutch which was used on some Dodge diesel pickups, and other vehicles:
http://www.ets.borgwarner.com/PDFs/Visc ... DirAct.pdf

http://www.youtube.com/watch?v=VxjfuJi4 ... re=related

It might be possible to run this on the CRD (if it fit) by using this PWM controller:
http://www.amazon.com/SPAL-Programmable ... B000M52VWI

This combination would cost many times what the Hayden severe duty fan clutch does, but it would be adjustable and perhaps save some fuel when not activated, due to less drag.

bugnout · **Posted:** Wed Jun 08, 2011 5:10 pm

i never had any issues with overheating until on the way home from this last trip from Moab. I had the needle peg out a couple of times on the way home, first as I climbed Monarch pass and again as I was passing other drivers in eastern Colorado. Shut off the A/C and turned on the heater to stop the needle climbing. CRD may be self protecting, but I didn't have this happen before.

I'm pretty sure that my fan clutch isn't working anymore. I haven't heard it kick on in quite a while. Ordered the Hayden clutch 2905 and the Nylon fan from the 02-07 gasser.

JL Rockies · **Posted:** Wed Jun 08, 2011 6:12 pm

That's the other part of it, other areas only have "mountains" to drive over so results may vary.

Roostre · **Joined:** Sun Oct 24, 2010 3:57 pm **Posts:** 195

The only time mine has gone very far to the right I was pulling a heavy trailer over the Sardine pass between Logan and Mantua... when not towing it stays dead center even climbing Parleys.

:2cents:

JL Rockies · **Posted:** Thu Jun 09, 2011 9:39 am

yes.... as stated a percentage of these rigs just run hot. no solutions available. years of posts without conclusion on here,

ATXKJ · **Posted:** Thu Jun 09, 2011 8:30 pm

Quote:

no solutions available

not buying that - the laws of physics work the same no matter where you are

the fact that you chosen not to purse the fix, is not the same as there being no fix.

Just sayin'

overheating

Who is online