Hi All,

I upgraded my truck to R134 a while back (cleaned system, new expansion valve, o-rings, proper oil and R134 charge) and it works great, BUT after 15 or 20 mins the system over-pressures. If I water down the condensor the pressure snaps back to normal. I've noticed that the fan clutch is engaging only intermittently and am wondering if it's nearing end-of-life.

Can anyone tell me how long they typically last? Not long after I got my truck, it needed one, though it had 195k miles on it at the time (not sure how many times before it was replaced). I've now got around 70k miles on this one and I would suspect that is too soon for it to crap out. I did use an OEM isuzu one and not an off-brand.

Anyone have any ideas? I'm hoping that it's just the clutch and not a function of the R134 conversion (higher operating pressure?). The pressure does run a little higher than it did with R12, I am running the proper oil charge and about 80% the R134 as the spec'd R12 weight. Cools fine until it over pressures or when I'm spraying a little water on it.

HEY TODD YOUR CLUTCH FAN MAY BE DYING ON YOU AGAIN, DO YOU HAVE ENOUGH ROOM IN THE FRT TO PUT A LARGE PUSHER FAN IN, AND HAVE IT ON ANYTIME THE CLUTCH IS ENGAGED ON THE COMP, IT WILL MAKE A LOT OF DIFFERENCE IN THE PERFORMANCE OF THE A.C SYSTEM , I HAVE HAD TO PUT PUSHER FANS ON A LOT OF THEM HERE AND IT ISNT AS HOT HERE AS WHERE YOU ARE AT, EVEN IF YOU HAVE TO USE TWO SMALL ONES IT WILL WORK BETTER ,JERRY

Thanks for the reply, Jerry. I tried to put in a 10" Hayden tonight, I have a few larger ones, but a 10" is the only one that is smaller in width than the condenser to mount it on. Well, there's not enough room by a long shot to fit the Hayden between the condenser and the grille. Doesn't look like it will fit between the rad and the condenser, either, not to mention I would have to dump the coolant and pull the rad or evac the AC and pull the condensor to install it that way. Not sure what to do now.

Does anyone know of a pusher that will fit between the condenser and the body on the 91 and earlier Troopers?

My last alternative would be to go back to the old electric radiator fan that I made for the truck a while back, but it seemed to cool a little too well on the radiator and produced larger coolant temp swings than I would like. If it makes the AC blow cold consistently I don't really care, though!

I put a 10" Hayden fan in my v6 90 Trooper. Put it in between the radiator and condenser. Needed to push the condenser out as close to the grill as possible, minor bending of mounting brackets. Very much worth the effort, I plan on doing the same on my 89RS Trooper.

Before you put an auxillary fan try this:
(See the link to ih8mud for details)

Clutch fan fluid swap

It worked on my 1996 Landcruiser... I used to have a 1990 Trooper and feel your pain on the A/C performance at idle.

greaux... thanks SO much for that link. It's great not only because I now know how these work, but I think I may try the fluid replacement. I may also try and do the Hayden 10" again if I can find a way to get it between the condenser/radiator without removing one of them.

Would you happen to have the p/n on that 10,000 cst oil? I looked through the thread but couldn't find it.

Thanks!!!

marcucci,

Not sure about the part number.
I ordered form this guy at Toyota.
Dan - 1-800-432-6668 Ext 8

I'll look for the part number too...

However, a lot of the guys have had success using
OFNA silicon diff-lock oil from hobby town USA.
About 9 buck for 50 to 75 ml.

HobbyTown

Check this link too if you use the hobbytown stuff:

Ih8mud

Let me know how it goes...

marcucci,

Here is the Toyota part number:

10,000 Cst = 08816-10001

10,000 Cst Toyota Oil

I really think this will solve your problem and the problem of others experiencing warm vent temps at idle.

P.S. I split the halves of the clutch and used a heat gun to drain the old fluid out. Then I added roughly the same amount of fluid - eye balled the amount in the clutch before I drained and compared the amount removed and added using two identical cups.

Fantastic! I really appreciate all the help. I will probably give it a shot, I have an extra clutch. Hopefully this really will solve the problem as it's a real pain in warmer temps. Just like you it works fine once you get moving and when the fan does actually engage.

Try adding a half a can of Freeze 12 to your system, if you have access to the fittings necessary to connect up to a can of Freeze 12 and a recovery system to remove some of the Freon 134A. Freeze 12 will drop the condenser pressure and vent temperatures quite a bit while maintaining the 25 to 40 psig suction pressure recommended for R-134 systems.