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IPM 08-16-2004 10:40 AM

ac belt routinely pops off 454
anyone else have this problem? My ac belt comes off routinely in my motorhome. I have installed an idler pulley to keep the belt from jumping so much between the compressor and water pump. That works well till the sealed bearing in the idler pulley wears out. Sure need a better solution.

Any solutions out there?


Galax bluegrass festival was great! Parking via the Walley club was well done as well. Weather was overcast but nearly no rain while we were there.

Motorhome pulled the mountains well, temp never got over 180F, of course I don't pull a toad and I'm only 28'.

swebster 08-16-2004 10:50 AM

My AC has two groves in the pulley. The belt runs around the water pump and around the AC and the Power Steering/Brake pump. Could yours just be misaligned?

IPM 08-16-2004 11:01 AM

One grove pulley in mine. Same belt routing as yours. Yep, the water pump pulley may be pressed too far toward the engine. Rather not change the water pump to test that theory....... but I've no problem with the water pump/alternator belt....

ac compressor looks aligned correctly, I've checked that over and over and over......

overlander63 08-16-2004 11:04 AM


Originally Posted by IPM
anyone else have this problem? My ac belt comes off routinely in my motorhome. I have installed an idler pulley to keep the belt from jumping so much between the compressor and water pump. That works well till the sealed bearing in the idler pulley wears out. Sure need a better solution.
Any solutions out there?

Do you have V belts or Serpentine belts on your MH? If you have serp belts, you might be able to find an automatic tensioner, basically what you have, only instead of a manual adjustment, it is a pre-tensioned spring. Also, if you are wearing out bearings on your idler pulley, you have the belt adjusted too tight. A LITTLE belt jumping between puleys is normal, and tends to be more pronounced the further the pulleys are apart.
I am sure you checked to make sure your pulleys are not bent, you may want to have the alignment of the pulleys checked.

IPM 08-16-2004 11:18 AM

v belts, the pre-tensioned Serpentine type tensioner is a great idea, pulleys not bent, waterpump pulley alignment suspect but not much, yep probably over tension the belt.

74Argosy24MH 08-16-2004 11:57 AM

There are short and long water pumps for BB Chevys and different pulleys for each. Short took a flat pulley. Long should have quite a bit of offset back towards the engine. Wrong pulley?


thenewkid64 08-16-2004 03:13 PM


Originally Posted by 74Argosy24MH
There are short and long water pumps for BB Chevys and different pulleys for each. Short took a flat pulley. Long should have quite a bit of offset back towards the engine. Wrong pulley?


When I did the water pump on my 76 all they could get was a short shaft, did not know there was a diff. Belts jumped (100 miles later and would not keep them on) had to shim the water pump pully out about 3/8 of an inch to get to all line up.

IPM 08-17-2004 07:57 AM

That must be the root of my problem. Wrong water pump. Wrong pulley alignment. Wrong pulley?

Not looking forward to replacing the water pump while the radiator is installed. I think I will also check on shimming the pulley out as well first.

thanks ya'll,


pillageTHENburn 05-17-2005 11:47 AM

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I realize this is an older thread, I may need to re-post this elsewhere. But I thought I'd give it a try...

I have a '74 Argosy MH, with a Chevy 454 on a p30. It recently lost a belt and I realized because it got hot (H2O pump quit), and now it would appear that it actually is missing 2 belts. I need to get a belt routing diagram! I have no clue how these should be set up. I've attatched a representation of the pulley layout, the numbers in brackets represent the number of pulley spaces on each shaft. There is currently one small belt that runs directly from the crank to the Power Steering (I think it's the ps) and that is it. I have a hunch that it may be incorrect, I have no idea how it was belted prior to me getting it. It may have been jimmy-rigged. Does anyone have any ideas!? No place here could get me a manual either. AGHHH!!

Thanks in advance for all the help!!

TomW 05-17-2005 12:20 PM

I have a 454 in my '84 Suburban, and it has three belts. Although I am not near the truck at the moment, I believe one belt services both the smog pump, and the alternator, another belt spins the water pump & power steering, and the remaining belt runs the A/C & water pump.

If you do not get better replies, PM me and I can pop the hood.


swebster 05-17-2005 01:19 PM

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Serpentine runs from Crank to Smog to Alternator to Water Pump. V Belt belt runs from Water Pump to A/C to P/S and back to Water Pump. "backup" P/S belt runs from Crank to P/S.

I also used to have a second Smog pump (part of the now removed A.I.R. Emissions system) that sat in between the Alt and the AC. But mine now looks like yours.

till 05-17-2005 01:21 PM

FWIW, how old is the belt, and have you tried fliping it around. I had a new belt that kept poping off. I fliped it end for end and the problem stopped.

Hippo 05-17-2005 01:34 PM

I had the same problem years ago. I found the AC compressor was not lined up with the other pulleys. Had to shim it and it worked.

pillageTHENburn 05-17-2005 03:39 PM

Mr. Webster, Thank you!! That is awesome!
The only question I still have is that all pulleys are v-belt pulleys...should I replace any of them with serpentine? I can still do what you've drawn with v-belts right?
Thank you again! Now maybe I can get this thing back home!!

74Argosy24MH 05-17-2005 03:56 PM

The belt on the LH side of the engine also needs to go around the crank pulley- crank, water pump, ac compessor, power steering. V belts are what you need. My LH belt is about 60" (Dayco 11A1535 15605 and it could be a little shorter that is why I say about 60"), no smog on mine so my length won't help.


pillageTHENburn 05-17-2005 10:08 PM

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Thanks John!
Yeah, the more I looked at it the closer I came to that conclusion, this way all three belts hit the drive pulley. Is this what you mean (see picture)?

swebster 05-17-2005 11:04 PM

That matches my setup

74Argosy24MH 05-18-2005 07:01 AM

And a third "that's it."


swebster 05-18-2005 08:31 AM

I would add that (at least on mine) the passenger side belt is a wide multi groove belt - bascially a serpentine belt. The others are V-Belts

pillageTHENburn 05-19-2005 02:58 PM

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Hey everyone! Thanks for all the help and advice!! Here's what ended up happening...

I was finally able to find a Kragen that would tell me where the belts should go (which pulleys each belt should hit). what they told me is noted in the first image... I tried it and quickly found that the belt from the crank to the AC rubbed on two other pulleys.
So I ended up running it like it is in the second picture. I hope there is no problem with running the AC pump strictly off of the H2O pump...

Thanks again for all the help!! Now I need to tackle the hot start problem (or lack there-of). I think I have it worked out, but as always advice is more than welcome!!

TomW 05-19-2005 03:08 PM

Stress wise, I don't think the dark blue belt may last as long as you would like.

If the pulley placement in the picture is fairly accurate, there does not appear to be a lot of belt touching the alternator pulley. If you start having weak battery problems, you may need to reconsider it's routing.

But hey! if that's the way its gotta be, then that's the way it is.


74Argosy24MH 05-19-2005 03:10 PM

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That is a lot to drive off 1 belt (water pump, alt, a/c) especially if the batteries are low and you are running the ac. Keep tabs on the long belt.


swebster 05-19-2005 03:48 PM

I would really encourage you to consider another belt where the light blue belt is currently shown (wp to ac). It should also go around the driveshaft pulley and the p/s pump.

Remember that the hydroboost pump in these babies provides power for both the steering and the brakes. If you loose or slip that one belt you're going to have a hard time controlling the rig. (Ask me how I know). I always felt like the belt from the driveshaft to the p/s pump was a "backup" for a failure on the other one.

I'll get you the belt number for that one from my rig.

Now - what's this hot start problem? There are a number of things you can do for this, some require sheilding or starter upgrades...and there is even a service bulletin on the P30 for this problem. (I have it somewhere)

TomW 05-19-2005 03:54 PM


Originally Posted by swebster
..some require sheilding or starter upgrades...and there is even a service bulletin on the P30 for this problem...


If the shielding involves the starter motor, I wouldn't mind hearing more about it when you get a chance to look for the bulletin.


swebster 05-19-2005 04:20 PM

Actually, it's about adding a second relay inline with the starter relay. I know too much about this relay as it was a constant source of failure on mine (mounted to the alternator bracket - it would basically break itself every 1000 miles or so). I can fax the bulletin to anyone who wants it. PM me you're info

swebster 05-19-2005 04:35 PM

Belt number 15605

pillageTHENburn 05-20-2005 11:35 AM

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The reason I was not comfortable with a big belt that ran from crank-ps-ac-H2O was because of the pulley sizes on the crank and the H2O pump...

There are 3 pulleys on the crank; The first two are the same size and the last one is *about* .5 -.75 inches bigger. The innermost (closest to the engine) pulley on the crank is running only the ps, it is one of the two small pulleys. So on the crank there are only two open spots, one is big and one is small. Now on the H2O pump there are 2 pulleys; one is a little bigger than the other. The small one is close to the engine and the big one is the furthest out. The big one is lined up with the Smog pump, the Alt and the big (outside) pulley on the crank. With one belt running from the crank to the H2O to whatever there is no issue, I figure if you add another one that runs between both the crank and the H2O pump then the pulleys need to be exactly the same size (proportionately). that is not to say that both pulleys on the H2O and both on the Crank need to match each other, but it there is a 6" and a 7" on the crank then the difference between the pulley sizes on the H2O pump need to be proportionately the same difference. If the pulleys on the H2O are also 6" and 7" then there's no issue... I'd have to do the math but if the small pulley on the H2O Pump is BIGGER than the small pulley on the Crank then the big pulley on the H2O pump would need to be MORE than 1" bigger (than the small H2O pulley). Have I completely confused everyone yet? I am NOT entirely positive that these fears are valid, this is just a guess. But the pulley sized didn't *look* like they were exactly proportionate, so I didn't want to risk it. I suppose now that the beast is actually home I could tear off the front end to measure the pulleys...heh. Any input on the subject?

On another note, the hotstart note in fact...

After some thinking and research I think that I have a rather good solution to the problem. The problem happens only when hot, it is a new starter. Some people at AC Delco said that the heat causes higher resistance in the switching wire (from ignition switch) and in turn it can not provide enough current to switch the solenoid on the starter. They said they can get a new "high heat" starter, but I didn't have $150 to throw into this. So I figured there'd be a better solution. In the three images attached (simplified slightly, starter and new solenoid are assumed grounded)...

#1. The way my starter is wired right now.

#2. Idea number one, splice in a solenoid away from the heat that can send full current to the starter solenoid AND to the switching terminal of the starter solenoid via a 2Ga wire.

#3 Leave the original main battery cable connected, add a new (10Ga) wire that runs from the batt+ to the new solenoid to the S terminal on the starter solenoid. Then switch the new solenoid with the same old ignition wire. This plan assumes that enough current can pass through a hot 10Ga wire to switch the starter solenoid. (this idea courtesy a mechanic who sold me a solenoid)

Whatcha' think? I think it'll work! I personally am leaning toward image #2; I'd like to have the assurance of a 2Ga wire that I am gonna’ get enough current down to that switching terminal...



swebster 05-20-2005 01:16 PM

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Number 2 is basically what the service bulletin recommends and is how mine is wired. I have a one year old "cheapo" starter from AutoZone and have never had a hot start problem.

One note on the remote solenoid. One style is mounted on a bracket - you do not want this one. On mine it was mounted to the top of the alternator bracket. The vibration from the engine would destroy the solenoid or break the bracket after 1000 - 2000 miles. I went through five of these before I decided to mount this style solenoid to the coach framing in the engine bay, directly above the starter (and above the exhaust manifolds. This other style solenoid has two tabs on it and flat mounts to the coach framing (you need to drill two holes for mounting bolts). By switching solenoids and mounting it there is is supported by the frame rail itself and isolated from the engine vibration. While I was in there I also re-wired with 8 gauge wire and, soldered the connections wrapped heat tape around the wire bundle near the starter. I run headers on mine which come very close to the original wiring for the starter. Since making this switch I have not had any failures.

This "bulletin" add on was probably the biggest and most frequent source of failure on my 345. At best, the engine vibrations would rattle the solenoid internals and I would not be able to start from the key and would have to hot wire it. At worst it broke off the mount and grounded out on a bracket, killing the engine. This happened a few times but once while crossing the Tappanzee bridge (mid bridge). I lost all engine power (and consequently power steering and power brakes) but was able to coast down the bridge and pull off...but those New Yorkers did not apprieciate my 10 mph crawl down the bridge.

Pic Below

pillageTHENburn 05-20-2005 01:45 PM

I showed my dad the plan, and he had some interesting questions that I didn't have answers to...
What is the distinct advantage of wiring a new solenoid in series? Why not just send a "hurkier" (bigger) wire through my ignition switch? If the problem is just reduced current through the small wire running from the Ignition switch then replacing it with a bigger one should solve it right? Is there anything that the extra solenoid does that a bigger wire can't do? Is there risk of toasting the ignition switch?


swebster 05-20-2005 02:15 PM

PM me your email address. I have the GM Service Bulletins for you.


74Argosy24MH 05-20-2005 03:04 PM


Originally Posted by pillageTHENburn
I showed my dad the plan, and he had some interesting questions that I didn't have answers to...
What is the distinct advantage of wiring a new solenoid in series?

I have seen the solenoid advised for a hot start problem and wondered the same thing, a solenoid in series with a solenoid. I think it might have something to do with Ford mounting theirs seperate from the starter and they really don't have as much problem as Chevy. But I can't understand why the second solenoid would improve voltage or current flow, just one more set of contacts to fail.

I have heard 2 explanations for the problem. First is the ignition wire as you said. Second is the post on the starter where the battery wire attaches expands and contracts and loosees contact. It wouldn't take much, these need all the current they can get to crank.

I think 2 ga. wire is heavy enough, it is what I have always used. Keep it as short as possible and make sure all connections are tight and clean.


pillageTHENburn 05-20-2005 03:23 PM


Originally Posted by 74Argosy24MH
...Second is the post on the starter where the battery wire attaches expands and contracts and loosees contact. It wouldn't take much, these need all the current they can get to crank.

It would seem that this problem would still be there with or without a second solenoid right? The battery wire is still going to go to the same post, just via a second solenoid this time. I'm about to just wire a Push Button Momenary in there with 0Ga just out of frustration!!! heh...

swebster 05-20-2005 04:10 PM

This may explain it. From the Chevrolet Dealer Service Technical Bulletin 78-T26:

"In some cases, the battery voltage available for solenoid operation is adequate when the coil is relatively cool, but is insufficient when the coil is hot. Typically, the voltage drop across the ignition switch, neutral start switch circuit to the solenoid should not exceed 2 volts. This, normally, would allow approximately 8 volts for solenoid operation. Unfortunately, the ignition/start circuit voltage drop can exceed 4 volts due to switch contact resistance, wire lengths, etc. Since the solenoid requires a minimum of 7 volts for positive operation, a marginal or "no start" situation can occur.

...(continued) The coil of the magnetic switch is connected in serious with the ignition/neutral start switch circuit. Maximum available voltage is, therefore, applied to the solenoid, since the voltage drop in the magnetic switch contact circuit is virtually zero".

Sounds like it's more about getting the resistance of the ignition circuit out of the loop between the batteries and the starter solenoid rather than "fixing" the "hot" solenoid. The ignition now simply closes the "relay" magnetic swich which direct connects the battery to the starter solenoid (12 volts), eliminating the voltage drop from the ignition/start circuit.

BTW - the bulletin also discussed and describes using heat shields, heat paint, etc to prevent a hot start as well.

74Argosy24MH 05-20-2005 04:14 PM

IMHO it won't make a bit of difference. A solenoid is just a glorified high current switch. In theory it should be about 0 ohms resistance, the same as the cable.

It doesn't amplify voltage or current, it can't pass any more current than the cable, maybe less if the contacts are pitted or rated for a lower amperage. How it can help is something no one has been able to explain that claims it is the solution.


swebster 05-20-2005 04:22 PM

No idea. Mine came with this already installed on it and I happened to find this bulletin in my manual when I was eating up these switches.

I've never had a hot start issue with mine so I can't say for sure if it "solves" the issue. Just passing long information that might help.

I'm no mechanic but the concept kind of made sense to me in that it didn't "amplify" voltage, it simply helped to remove resistance from the solenoid circuit by using a "relay switch" getting the solenoid at least 7 volts it needs to engage.

It's a $13 part from it's not a big deal to try it and see.

ALANSD 05-21-2005 02:34 PM

I put a thermal wrap around my starter and the wires and also went to a aluminum jacketed starter with enclosed solenoid. No heat problems since then at all.
I f you have a recent starter the jacket and wire insulation might be enough to do what you want. Its inexpensive also.

IPM 08-06-2005 08:41 PM

if you go over to driving the ac compressor directly off the water pump only, use no larger than a dayco 15450 v belt as it places the compressor at maximum travel. I've gone over to this setup as I'm tired of the ac belt, 15605 (60.5"), jumping off often.

IPM 08-07-2005 08:47 PM

Marginal success with driving the ac directly off the waterpump pulley. Put alot of stress on the belt driving the water pump and it broke. Oh well.......

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