• Welcome to The Truck Stop! We see you haven't REGISTERED yet.

    Your truck knowledge is missing!
    • Registration is FREE , all we need is your birthday and email. (We don't share ANY data with ANYONE)
    • We have tons of knowledge here for your diesel truck!
    • Post your own topics and reply to existing threads to help others out!
    • NO ADS! The site is fully functional and ad free!
    CLICK HERE TO REGISTER!

    Problems registering? Click here to contact us!

    Already registered, but need a PASSWORD RESET? CLICK HERE TO RESET YOUR PASSWORD!

Anybody Have Experience Replacing R4 Compressor with Sanden

JMJNet

JMJNet

Recruit
Messages
2,363
Reaction score
920
Location
Richardson, TX
It looks like the AC System in my 95 Suburban is on the way out.

Anybody have any experience replacing the outdated R4 compressor with the Sanden Compressor?

If so, what do I need? Bracket, lines, etc.

TIA.
 
Not sure, but I think you would have to completely rework your A/C lines and move the A/C compressor up higher to fit a SANDEN into the place of the older radial compressor. I can't remember right now, but I thought the compressor was mounted fairly close to the passenger side cylinder head, so you would have to relocate it up higher to do it. If your original made it this long, then I would buy a new one and put back on it. They aren't that bad of a compressor when they are working, and it would be your easiest option. otherwise you would have to change over to 96 accessory mounts, find a good used 96-99 compressor hose assembly(they are discontinued now and NONE are available anymore), and then you could bolt on a SANDEN unit for the 96+ trucks. Keep in mind you need a LARGE volume compressor to do the job as the dual A/C BURBS need at least a 10 CU feet per minute compressor to run both units.
 
Thanks for the reply. I thought the compressor is very close to the valve cover.
The Sanden is longer. There are some company selling some bracket for it and the purpose may be to raise it.
Mostly designed for Caddilac sedan but I have not seen their AC setup.

The current one was installed 4 years ago.
It is still cooling occasionally like on Sunday, it was blowing hot air.
Yesterday, it was blowing cold air.
I did put some extra refrigerant at the end of March.

Last year, the clutch started to get noisy (clicking), now there no clutch noise anymore so I am not sure if the clutch is enganging or not.

I am going to try to put in a new Cutoff Switch, which I replaced last year.

Not sure what is going on??? Any insight.

Hopefully by moving this to the D-max section, I got more answer. LOL!!!
Not sure if AC is interior components since most of it is under hood that is having issue.
 
First time the AC quits cooling well you need to stop using it immediately and fix it before using it again. I explain below. Your symptoms describe a system running low on freon with excessive clutch cycling - it is as bad as running your engine out of oil.

I wouldn't bother with a different compressor. Money is better spent on cooling upgrades for the condenser. I would buy or order a "NEW" compressor only. Reman units can (and more often than not) trash the entire system requiring lots of other parts to be replaced and you are out the 4LB of freon... Not worth the risk on this design esp since Harrison stopped rebuilding these units due to high warranty return rates.

You do need to understand that running the system low on freon is turning the compressor into a debris bomb that is contaminating the entire system. When the system is low on freon it has trouble getting oil to the compressor. The compressor has no oil reserve so if oil isn't coming in the suction port it is running dry. This is why our system is a 'flooded' evaporator type system. The evaporator has to have enough liquid freon to bring the oil through the evaporator. Oil moves in the liquid freon and gets left behind from the gas in the evaporator. If it is low on freon the oil doesn't get all the way through the evaporator as there is only gas at the top of the evaporator. The compressor starves for oil in this case. It is cheaper to fix the system now and STOP USING IT TILL IT IS FIXED! If you catch it before the compressor becomes noisy or runs out of oil repairs are an evac and freon charge with oil. After the compressor becomes noisy you are replacing a lot of things filled with compressor debris. For example: compressor, o tube, accumulator, condenser and flushing the system. On rear air systems you also have to replace the TXV valve in the rear evaporator. The TXV valve needs to be serviced with a compressor failure or you are being ripped off with a debris source left in the system and poor rear AC performance from a plugged screen. This is not a fun or cheap job...

The system has to be flushed with a compressor failure - no excuses or you get to do the job again.

With these systems an evac and recharge every single year with a leak check is money well spent. This system and esp this R-12 design compressor are known to leak especially when pushed to their limit on the R134A. Keeping it full of freon will keep the system at the fix the leak/replace leaking compressor stage without the added cleanup cost of the debris from a oil starved compressor. Sadly even then the compressor likes to blow. A different compressor will also burn up if the system is low on freon due to lack of oil getting to the compressor. This low freon failure mode is why a different compressor is not worth it. The cost of conversion could be spent on yearly service of the system to prevent failures instead.

Keeping the radiators clean and fan clutch in good shape is also critical and often overlooked cause of AC failure. A fan clutch over 5 years old is shot having lost 200 RPM per year.

More info on the system with photos of what is in a TXV valve after a compressor failure:
http://www.thetruckstop.us/forum/sh...fo-Yes-it-has-a-Thermal-Expansion-Valve-(TXV)
 
Thanks for the insight.

Which condenser do you suggest?

It was a new compressor put on less than 4 years ago.
Any particular brand of compressor better than others?
I know ACDelco is one but I see 4Season, and so on.

Is the debris usually collect at both the TXV and O-tube?

Sounds like the compressor life is only 5 years from your description.
 
I got a condenser from the dealer and had to order the new condenser brackets to fit as it is thinner than the OEM unit.

Any "new" compressor is ok. I have had dealer ones fail in 6 months due to a defect.

You have to pull the system down and then look at the o-tube and amount of debris in the system to decide if you need to change the condenser. First you need to find the leak if any.

Our old hoses at the crimps, condenser at the big square crimped part, compressor outer body are all common leak points. You can have the hoses rebuilt as they are rare diesel specific parts. Gas engine ones have different angles where it matters.
 
Get it on a set of gauges and see what the head pressures are. You could have a bad expansion valve or a plugged screen for it in the rear causing your issues. And a word of warning, MOST parts for the A/C on these trucks are discontinued. I just had to put 96-99 lines on my BURB because the 94-95 lines are no longer available for the rear unit. Throwing parts at the A/C is an expensive way to go about it, so buy some gauges if you don't have any or find a shop who has the equipment to check it. And run good parts on it as most of the stuff you buy from AZ and advance is worse than the junk your replacing.
 
Thanks again.

I called a repair/mechanics/body shop today that can take a look tomorrow.
I know a place who made high pressure hoses (hydraulic shop) which I plan to rebuild the hoses anyway if we need to fix this time.

Where the rear expansion valve? is that at the back opposite the spare tire?

I saw Napa sells a kit with compressor, o-tube, exp. valve, dryer, oil.
Is the NAPA compressor ok? or better found a AC supply shop?
I am in DFW TX, most of the AC supply shop seems to run from here or Arizona.
 
AC hoses should be made at an AC shop unless the place makes AC hoses on a regular basis. 134A has to have barrier hose or it leaks through the hose.

Pics of the expansion valve are here: http://www.thetruckstop.us/forum/sh...fo-Yes-it-has-a-Thermal-Expansion-Valve-(TXV)
The evaporator is removed in this pic, but, GM put it in the box with the evaporator. You can carefully cut the box open or take the lid off to get to it.

X2 on diagnose the system and see what needs to be done first. It is a good idea to get a 2nd opinion on AC repairs. Last time I did the AC on our 95 Yukon I paid $800 for the dealer to swap the compressor with the lifetime dealer warranty on it. Simply because I was tired of changing them out so often. I made money on that... It then went on to burn up the power connector under the dash and couldn't cut it out here so we found something with rear air.

Since that time I have learned that issues cooling the condenser were burning up compressors:
1) The oil cooler gets a mat behind it.
2) The factory 6 blade fan is garbage. 9 Blade or Duramax fan is better.
3) Electric pusher fan on condenser wired to the compressor with it's own relay helps cool down after engine start up. (Done before I knew about the 9 blade or Dmax fan.) It also helped compressor life.
 
A big disadvantage to doing this conversion is getting a smaller compressor! :yuck: You will need a compressor as big or bigger for the dual air Suburban as the factory one is almost too small.

The R-4 displaces 11ci. Or 180.26cc.

The biggest fixed displacement Sanden is 154.7cc

http://www.sanden.com/index.php?tag=U5H0AMX7Q

Also the R4 takes PAG 150 OIL and will not tolerate Ester oil.
 
WarWagon, which source of R4 compressor that you have good experience with?

Is the 9 blade fan can be put into the existing clutch? This is probably the easiest mod to do and cheap.
 
JMJNet said:
WarWagon, which source of R4 compressor that you have good experience with?

Is the 9 blade fan can be put into the existing clutch? This is probably the easiest mod to do and cheap.
Click to expand...

Watch the port heights on the rear of the compressor - they better match the one that comes off your vehicle. The R-12 and R134A years have lots of differences. ports are where the AC hose manifold goes.

Brand New Oreilly-Murray (four seasons) Texas USA made is what I am using now on the 1995. Got 2 years on it now.

Sadly I had to get a reman as no new ones were available for the 1993 and it puked a clutch. I got the warranty exchange and just swapped the clutch to save evac and recharge costs.

The 9 blade steel fan needs a new 4 bolt clutch. You have a 6 bolt fan and the 9 blade is a four bolt fan. If you are not shy about trimming the fan shroud get the Duramax fan as it moves more air at idle. I have run both fans and run the Dmax fans now as the 9 blade was ruined when we hit the Elk. I recommend the Kennedy Diesel low temp clutch because if locks up sooner and keeps the condenser cool. I use a 180 T-Stat and do not have unlock issues with the clutch. I really love the low temp clutch both for keeping me below 210 no matter what I pull and AC performance.

To be clear all fan clutches except the thread on are 4 bolts to the water pump. The difference is 6 bolts to the fan in 1995 and 4 bolts to the fan from the clutch in 1998 and Duramax. You will need a new clutch for the newer fan...

1998 is the 9 blade fan and proper clutch to lookup.
2002 Duramax fan will work with a 1998 clutch. Both work with the low temp KD clutch.

The factory 6 blade 6 bolt fan is garbage...
 
Thanks. I got it.

The mechanics evac the system and it only has 3 lbs of refrigerant.
So definitely there is a leak.

Sounds like the Four Season is probably good.

I plan to change the hoses assembly also.
 
WarWagon said:
A big disadvantage to doing this conversion is getting a smaller compressor! :yuck: You will need a compressor as big or bigger for the dual air Suburban as the factory one is almost too small.

The R-4 displaces 11ci. Or 180.26cc.

The biggest fixed displacement Sanden is 154.7cc

http://www.sanden.com/index.php?tag=U5H0AMX7Q

Also the R4 takes PAG 150 OIL and will not tolerate Ester oil.
Click to expand...

The R-4 is available in 8-11 cu ft of displacement, so be careful of remans as many out there use the 8 or 10's for there reman units. And the SANDEN SD7H15 works just fine for a dual air unit as that is what is on mine now. Also it may be noteable that 96+ trucks use a 10 cu ft output H6 compressor. Now MOST SANDEN swaps use the SD5 compressor as it is pretty compact, but it will not stand a chance at a dual A/C unit.
 
Thanks for all of the useful data, Gents.

I just recharged my system today, and added a big air dam under the front bumper (homegrown). It should decrease airflow under the Burb while forcing more air through the cooling stack.
I have a very good radiator and A/C shop not too far away. Last year they replaced the schrader valve on the compressor, along with the flush and refill R4. They had warned that the compressor might be leaking, but the pressure held while they tested it. The Burb is a very large solar oven if the A/C isn't working right. I also removed the rubber and foam cover on the blower motor to check the connections and was able to lube the exposed bushing and shaft end. I didn't reattach the cover for 2 reasons; my size 12s fit better under there now, and it seems like it should keep the motor cooler.

The blower motor was occasionally squealing on braking but not on acceleration. It's the original 1994!

Subscribed, with free babbling included! :hihi:
 
THEFERMANATOR said:
The R-4 is available in 8-11 cu ft of displacement, so be careful of remans as many out there use the 8 or 10's for there reman units.
Click to expand...

Any pointer on how to identify the bigger one?

I notice, sometimes it said LTR4?

So far, the AC works after putting 4lbs back in it.
We will see how long it last.
 
Can't say I have had any luck with the R4's. I have had to change both of them this year. (The reman and the new one.) The Reman unit actually lasted longer if I don't count the clutch failure. Reman 3 years and new one 2 years (and just barley got warranty on it). Both failed at the body o-rings. IMO the higher pressures from the high AZ summer air temps stress this failure point harder.

I wonder if the Sanden units last any longer?
 
WarWagon said:
Can't say I have had any luck with the R4's. I have had to change both of them this year. (The reman and the new one.) The Reman unit actually lasted longer if I don't count the clutch failure. Reman 3 years and new one 2 years (and just barley got warranty on it). Both failed at the body o-rings. IMO the higher pressures from the high AZ summer air temps stress this failure point harder.

I wonder if the Sanden units last any longer?
Click to expand...

I can imagine the hot AZ summer can kill AC system fast.
 
I had good luck with sanden, several friends use them for their on board air systems as well. Clutch is the weak link on it so no real worries. I suggest when the clutch goes just change the whole compressor, they dont always reseat on properly. A better tool out there for centering would help but unless someone put one on the market in the last 3 years they all suck. Maybe 60 - 70,000 miles is about it for the clutch to be gone.
 
You must log in or register to reply here.
Back
Top