05 grand caravan 3.3L keeps burning up a/c clutch

nickb2

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#31
I think amp draw was already posted, but here it is again. 3.3amps for the denso model 10S17 @ 21F @12 +- 0.5v. 2.2amps for the 10S20 model @ same v and temp.
 

nickb2

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#32
If amps are within specs, you must look elsewhere. Especially after 6 new clutches.

As sherlock holmes likes to say "when you have eliminated the impossible, whatever remains, however improbable, must be the truth?"
 

nickb2

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#33
Also, don't rule out crankshaft and idler pulley misalignment. Another thing that is notorious on these soccer mom vans.;)

A misaligned belt could be causing this all along. A misaligned belt will cause such issues as the gap is no longer under specs when under load and misaligned. I hope that makes sense to you, it sure does to me as I have seen that in the past. Just not as often as your experiencing.
 
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#34
Thats funny because they make an aftermarket tensioner because these vans are infamous of throwing belts. But this one has never had that issue. I will check alignment and amp draw in a.m. Thankyou all for your input. I work alone and often other shops only look at me as "the enemy" so bouncing ideas off others can b almost impossible

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nickb2

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#35
Hey, I had my own little shop for 5 or so years. I know what "the enemy" feels like. Especially when you do better work for cheaper.

Nature of the beast.

Never leave a stone un-turned. Some is always watching for you to take a false step.

Keep coming back, you will see that we are not the enemy. Quite the contrary.

Peace out, have loads of work to do for my new job that pays me to not face the enemy anymore. But it was a freaking blast while it lasted I must say.
 
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#37
Welp, after much frustration and electrical issues beating me to the point of insanity.... Thinkin we got er licked!!! With new relay wired in, new rad/cond. fan pressures are good again. Got 35 psi on low and 240-250 psi high side @ 90f (cant find degree symbol). Ran a/c for abt. 2 hrs with 15 mile road test. Both front and rear system blowing cold. Thankyou all for the suggestions. Will definitely b part of this site if i can figure it out.lol

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#38
R-12 pressures increase at a linear rate, R-134a at an exponential rate, tube and fin condensers could be flushed out, parallel flow condensers are throwaway. Not only good air flow is necessary, but if any debris on the inside, cannot be cleaned, another thowaway.

Two possibilities, old compressor was seized putting debris in the condenser, or the system was opened without flushing, deep vacuum, and injecting in new PAG oil, a women's facial cream, exposed to any moisture forms a sludge that blocks the condenser. Stick gauges on it, at 80*F high side pressure should be around 225 psi, seen some well over 300 psi, even close to 400, this puts one heck of a load on that clutch, could well be your problem.

R-12 never had this problem with mineral oil, working on an R-134a system can take many more hours of work. Another sore problem is the evaporator orifice itself, also blocks refrigerant flow.

Yet another over a hundred year old problem, that radiator is a bug collector restricting air flow, became even worse with aluminum heads, made even worse by adding a condenser in front of it. Even worse with with FWD cars with electrical fans. Can't have air conditioning without airflow. These have got to be kept cleaned.

Just saying your clutch may not be the culprit, but the victim of these other circumstances. On single drive belt systems that water pump also sees this extra load, namely by the AC compressor putting a huge load on it. Never was a problem before with multiple belts, sure is now, water pump is the weakest link.
 
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#39
Can also be a problem with the clutch coil itself, way to test them is to apply 14 V to them, can use your battery in series with an ammeter. Hook up a charger, if say the current is 4 amps, after an hour or so, don't have to stare at it, that current should go down because the heat increases the resistance of the coil.

Could run into one where the current increases, even drastically, using a random wound coil with magnet wire, and even though the current increase, the ampere-turns decreases causing a much weaker magnetic field.

Would not be a problem if layer wound and varnished, but bean counters don't like this.
 

nickb2

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#40
Yet another over a hundred year old problem, that radiator is a bug collector restricting air flow, became even worse with aluminum heads, made even worse by adding a condenser in front of it. Even worse with with FWD cars with electrical fans. Can't have air conditioning without airflow. These have got to be kept cleaned.
You are fabulously correct. I have seen many blown clutches due to clogged condensers or just plain as you say, full of shyte or bugs or even just bent cooling fins.
Two possibilities, old compressor was seized putting debris in the condenser, or the system was opened without flushing, deep vacuum, and injecting in new PAG oil, a women's facial cream, exposed to any moisture forms a sludge that blocks the condenser. Stick gauges on it, at 80*F high side pressure should be around 225 psi, seen some well over 300 psi, even close to 400, this puts one heck of a load on that clutch, could well be your problem.
 

billr

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#41
Earlier there was a post indicating the high-pressure switch doesn't trip until 447 psi, and the mechanical relief valve is even higher at 500-600 psi. It seems odd those would be so high if the system can't withstand those reasonably well, including the clutch.
 
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#42
Thats true the cut out is extremely high. But have witnessed it operate at 450psi when cond. Fan wasnt operating properly on a different caravan. But side note: went to parts house today and they offered buying me one from Dodge directly due to Murrays awesome amount of bring backs this month.lol

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