Sunday, April 22, 2012

About Time for a Timing Belt

I replaced my first timing belt at around 70K miles. I just edged over 150 and figured it was about time for my second. In preparation I decided to try one of the inexpensive kits offered by several dealers on eBay. In my case, the kit was "on sale" for around $130. The kit included the water pump, tensioner pulley assembly, idler pulley and a good aftermarket belt. All the parts were Japanese or Korean. Doing some research I decided to use the excellent instructions available from VX owner Bart on the forums: nfpgasmask here: He made some additional recommendations so I purchased a new tensioner and a new water pump stud (got those from Merlin at St. Charles Auto: 1-800-727-8066). Since the serpentine belt I had on it looked decent, I deferred on that (it's easy to change anyway).

I had also decided that while I was in there I may as well upgrade the radiator hoses to silicon - I purchased these from SVX Motorsport ($140 Plus shipping: ). I also purchases some excellent Stainless Steel Constant torque hose clamps from a dealer on Amazon:

I decided to take a couple of days off from work - had a week left over from last year plus I wanted to be able to access any parts stores if I ran into an issue - since most are closed on the weekend it's just easier when things go South. I put together my tool kit and parts and headed outside about 10:00 AM. Here's a couple shots of the VX before I started.

Here are the parts from the eBay kit:

Japanese-made idler pulley
Korean-made tensioner assembly
Not sure where it's made, probably Taiwan
Brazilian-made water pump
Some general impressions - the pulleys both seemed to be of good quality - time will tell. The belt also seemed very well made as did the water pump. It did have cast fins instead of the bent-steel of the original - also the gasket was paper instead of the original metal. I figure that if something goes wrong I'll just take it apart and use real OEM - I'll only be out the $150 and since the VX has a non-interference engine there isn't too much risk of damage.

Here are the OEM parts I used:

And here are a couple of extras (the thread-lock is needed for one of the bolts in the water pump):

New pure silicon hoses and clamps:

Tools, consumables and the drip pan:

These are the dissembly photos:

Sans Serpentine belt

So here is when things got interesting:

When you pull off the old timing belt, the cam pulleys are supposed to move inward to the 12 o'clock position (according to Bart's excellent guide) - instead mine went to the outsides:

Right Cam Pulley

Left Cam Pulley

I continued with the dissembly:

New water pump, stud and idler pulley on the top and right
Tensioner Pully Assembly on the left

So now the first problem. Take a close look at the tensioner pulley assembly on the left. That's actually the original assembly with a transposed pulley. When I compared the original to the replacement it was quite evident that the offset (distance from the front of the motor to the inside edge of the pulley) was incorrect. There's a difference of about 4 or 5 millimeters - no way the belt would have tracked right using the replacement. I ended up taking both to the bench and using a vise to hold things down, removed the pulley - luckily the inside shaft had the same diameter so I went with the new pulley instead of replacing the old.

So at this point I called it a night and posted a question about the cam pulley placement on the forum. I also took another look at the videos available there regarding the timing belt. Some helpful guys chimed in and I decided to go for it, cranking the cam pulleys inward instead of outward. The opinions were that it shouldn't matter as long as everything lined up.

The next morning I took a look at the belt and came to problem number two with the kit. OEM timing belts have two marks (one for each cam pulley) and a dotted line that you align with a notch on the back of the drive pulley. This "ITM" belt had four marks and none of them lined up with anything - also the marks were on the "gum" side of the belt instead of the edge of the "tooth" like and OEM belt. I selected one of the marks as a reference, placing some blue painters tape next to it to indicate where the tooth was and counted to the next mark (53 teeth for reference) - there I placed a mark with a sharpie and a piece of tape with arrows:

Right Camp Pulley Mark
I then counted to the next line on the original (71 teeth if any one's interested) and placed repeated what I did for the prior. Just for piece of mind I counted to the dotted line and they were the same from both both belts, so I knew the belt was the proper length. I then went back to Bart's directions:

Right Cam Pulley with everything lined up

Left Cam Pulley with everything lined up

Drive Shaft Pulley Lined up

So here it is with the belt completed and the tensioner released. I spun it a couple of times to make sure the marks and pulleys lined up (you lose the marks on the belt) and everything looked kosher.

There were a couple of parts that were a bit rusty that I first cleaned off with mineral spirits and then shot with Rustoleum:

Repainted Skid Plate
Drive Pulley
Finally I put everything back together:

And added the new hoses, reconnected everything and filled the radiator:

Here's a video I shot of the VX when I first tried the ignition with the new bits...

What you don't see in the video - after another minute the Check Engine light came on - doh! Got out my reader and it was showing a P0104 code - something about a lack of air pressure on the MAS - got out and checked the connection and of course I had forgotten to attach. Did so, cleared the code and the VX was ready to go.

Finally reassembly took about another hour - I took time to clean everything off really well, especially the radiator and areas behind the cladding. I waited until the next day for the test drive since I wanted to top-up the tranny. I ended up losing a lot more ATF that I expected - needed more than a quart to get it topped up.

Here's a couple of photos of the actual tools I ended up using:

Used the impact wrench to remove the drive pulley

In all the entire experience wasn't bad, especially since I took my time. I think this will be the last time I do any major repair like this myself - my back was really sore after each day from bending over the fenders and front - guess I'm getting too old for this kind of thing. The other thing - some of the torque settings seem really lighter than they need to be - the water pump for instance. I wanted to over-tighten the bolts as they just didn't seem to be very tight - if anything fails it'll probably be due to my going an extra half-turn...

For reference, the seller of the kit I purchased on eBay:

Item Title: 99-01 3.5L Isuzu Vehicross Timing Belt Seals Water Pump
I purchased on 5/22/2009 (yeah I know it's been a while)

The part that was incorrect:
Roller Tensioning Bearing
Box is marked: GMB Tensioner & Idler Bearings
Made in Korea
Belt Tensioner 8-97116-002-0!

I'm not sure if the seller put the wrong component in the box or if the kit was just mis-configured but thought I'd share the numbers in case the kit is still wrong. Here's a link to a current auction for the equivalent on eBay by the same seller:

It's now Sunday so I've run the VX several times without any issues. I'll report if there are any failures, etc.

-- Best, John

Wednesday, March 28, 2012

Replacing the VX Blower Motor for AC/Heat

So sometime last year I started to have this intermittent problem - from time-to-time when I'd start the VX and the blower fan for the AC wouldn't cut on. I could feel cold air coming from the ducts when venting to the outside, but when on recirculating I couldn't feel anything at all. I did some checking around and found that the most likely culprit was the blower fan itself. The two other possibilities were the Resistor for the system (when this is bad the air comes out full-force and you can't dial it back) and the Climate Control panel itself. I started calling around for parts figuring I could pick up the blower motor and resistor and work backwards. Unbelievable how much they are from Isuzu. I managed to find an aftermarket blower motor on Amazon for $47 shipped and started with that. It came in the mail last week and I went about on Saturday replacing the motor.

First thing you need to do is remove the glove box. If you haven't done this yet, open the door and squeeze the compartment together near the pins that hold to the top to the sides. This allows the door to swing free downward. Next there are four 10mm bolts that hold a bracket at the bottom to the dash frame (the hinge side of the glove box mounts to this bracket).

The motor hangs from the bottom of a plenum on the right side - there are four screws you need to remove which allows it to come free. Careful with this as there's a basket fan attached to the top which you'll need to reused. The screws in back in my VX were a bit corroded so I cleaned them up before replacing.

Original Blower Motor Installed

The new fan comes in a generic "Made in China" white box - PM3914. It's shaped a bit different from the stock blower motor - basically a small DC motor mounted to a metal plate instead of the formed plastic of the original. Also the heat vent in the new is a thick flexible tube instead of part of the molded housing of the original.

The looks don't matter much here as the entire unit is behind the dash and difficult to see unless you stick your head way up under there.

The old housing "squirrel cage" or basket fan was fairly dirty - be very careful removing the retaining clip on the shaft. The instructions suggested cutting it off which I did. There was a bit of rust on the shaft so I smoothed it out first with some fine sandpaper. When pulling up the basket pry-up from the bottom - don't risk busting the fins on the sides.

The new unit comes with new clip for the shaft (it's in a small zip-lock with the instructions). Before replacing the basket clean it off well. I used throttle body cleaner (plastic safe) then scrubbed down with soapy water, drying with a blow dryer before putting it on the new fan.

Once the basket it on you can fit it up into the housing. The rubber tube fits to an opening where the molded plastic used to fit. Dry-fit first - you'll find that there's a fairly substantial gap between the metal plate of the new blower motor and the existing housing. Look in the box and you'll see three thing back-adhesive weather strips - these are garbage. I used adhesive backed felt instead (happened to have a few sheets of it). You'll want something that will compress down when you put the screws back in.

After-market blower motor installed

The new fan doesn't come with a connector that will fit the existing wiring harness, however the spade bits do work. Fit the black from the motor to the blue wire with black stripe from the harness, and the blue from the motor to the blue wire with white stripe from the harness. Start your ignition and try out the system before putting everything back together. Once you're satisfied, you can either rig something to hold the motor to the harness; direct connect the wires with solder and shrink tube; or simply tape things up with electrical tape (I did the latter - not much chance of bumping the connector to make the tape come loose).

Put the glove box back in and you're done. The whole job takes about 30 minutes. You'll need a Phillips bit screwdriver and a 10 mm socket with extension. Some electrical tape and something to use as a compressible gasket (I used felt). The results were much better than I expected with a super-strong flow of air. I hadn't realized how weak the system had become with the old, failing motor.

-- John