My ‘94 2WD Blazer - Build Log

I recently picked up a ‘94 S10 Blazer W vin with 140k miles and some issues, but in pretty great condition otherwise. I’ve been a C10 guy my whole life thanks to my dad, but can’t afford one with how crazy they are now. I had never really paid attention to S10’s til I saw a nice one at a show in July, and a few days later I was head over heels for this one I found on facebook. Here’s the post I made in Member Rides when I bought it

There’s no real point to posting this, just a brain dump of what has engulfed most of my free time the past few weeks and a bit of a build log. It’s going to be long and verbose so I don’t expect anyone to read it all, my friends just aren’t really gearheads so I gotta put all this somewhere lol.

I’ve never undertaken a job this big before and I’m doing research and taking it slow every step of the way to make sure I don’t screw it up. I can only work on it 3 or so hours a day during the week so progress has been a bit slow. I threw the rule “don’t fix it if it ain’t broke” out the window for this project since it’s going to become my new daily, and since I already had to pull the motor to swap the freeze plugs I wanted to make sure it wouldn’t need to come out again for a very long time. I listed most of its issues in the previous post I linked, so I won’t restate them all here. In short, it leaked coolant, oil and ATF, misfired at idle and ran super rich, motor mounts were shot and A/C didn’t work, among other things. I say those in past tense in hopes that they’re all resolved after the motor goes back in tonight.

I started by swapping plugs, wires and O2 sensor cuz it was reading lean despite running rich as hell, thing was CAKED with soot, much like my garage floor below the tailpipe. The speed sensor at the transmission output shaft was leaking a ton of ATF, so I put in a new one which was a bit of a pain since it was pretty baked in and there wasn’t much to grab onto, but some wide jaw pliers and PB Blaster did the trick. I used a bit of oil and some clamps to press the new one in.

Next I hooked up a fuel pressure tester and it built full pressure, but leaked down to 20psi in about 5 seconds. Opened up the plenum and watched the CPI regulator spout a healthy stream of fuel, but lines/poppits seemed okay, so I just bought a new regulator and nut kit for now - regulator was $10 in a closeout sale on rockauto so I went ahead and bought a spare just in case. The nut kit was out of stock basically everywhere, but thankfully PartsHawk had 2 left.

Yuck. Hard to believe the driver’s side is closer to how it should actually look than the passenger side.

I then tried to do my lower intake gasket while waiting until I could pick up my dad’s engine hoist, but with no guide pins and no extra set of hands I wound up sliding that thing all over the place before I got it lined up, not to mention I didn’t use thread sealer nor apply RTV around the coolant channels. The original gaskets had bonded to the heads on a damn near molecular level and were an absolute nightmare to clean off; that was the worst part of this entire project, but would’ve been much easier with a fine chisel/scraper rather than the loose razor blade I used.. I also wound up bending the fuel inlet/outlet lines a bit when removing the intake (you can see they’re slightly askew in the pic below), so hopefully those are still okay.

After that endeavor I got most things disconnected, pulled the rad, fan etc., and picked up my dad’s hoist and a friend’s engine stand. Previous owner said he had replaced the dist. cap and rotor but they were super corroded when I pulled them, so added another few parts to the list. Since I had the plenum off I was able to get to the top 2 trans bolts with a wrench, though I’ve never spent so long unscrewing a single bolt so that led me to pick up a ratcheting wrench the next day lol. My dad’s buddy lent me a custom 3’ extension he made which made fairly quick work of the other 4 bolts. Managed to only snap one exhaust stud, but sadly the other studs unscrewed rather than the nuts coming off of them so I’m going to have a heck of a time getting those out of the y-pipe flanges tonight.

With the trans, torque converter and exhaust unbolted only a few brackets and ground straps remained, so I put a 6x6 block on a jack to support the trans, hooked the hoist up to the lift brackets bolted to the intake and raised it enough to get to the rear grounds. With a few more pumps of the hoist and a bit of prying near the guide pins the motor was finally free. I cracked a celebratory beer and proceeded to mount it up to the engine stand with some 3” 3/8”-16 bolts - for what it’s worth, they were about half an inch too long for the harbor freight 1/2 ton stand I’m using.

While mounting it to the stand, the knock sensor on the passenger side rear crumbled with a light tap of a ratchet handle, as did the oil pressure sensor. I was contemplating replacing those anyway, so that made the decision for me. I then got the passenger side accessory bracket off, and was annoyed to discover I had to rent a puller to get the P/S pump out of the driver’s side to get to the last bracket bolt. With that done, I finally got a good look at the freeze plugs:


They came out relatively easily with a hammer and socket extension/flathead screwdriver (there are 8 total, just took the pic halfway into the job). As you can see, they were in pretty bad shape lol. I popped them all out, got all the rust chunks out with a magnet and screwdriver and then ran a hose through the holes for a while til it ran clear. I won’t bother posting a video, but I’ll just say there was about half an inch of dexcool sludge in the bottom of the channels in some spots, so it was more mud than water at first. With that done, I grabbed a big socket and hammered in the new brass plugs:

Also threw on a new water pump while I was at it. Shiny.

Next I pulled the oil pan, and was pleasantly surprised with the cleanliness inside. I noticed my rear main seal was leaking slightly, so I replaced it which was WORLDS easier than when I did the same job on my 350Z. New melling oil pump and pickup went in too. I installed the pump, measured the depth of the pan and marked the pickup before removing the pump and hammering it in to make sure it was the proper distance from the bottom of the pan. The pickup was a bit of a pain to get pressed into the pump, but once I stopped babying the hammer it went right in.


With that done I cleaned up the faces, put some black “Right Stuff” RTV in the corners around the main seals, popped the new gasket on and torqued the pan down. My 350Z just uses RTV as the pan gasket which was not fun, so this rubber gasket was awesome.

At this point I took the intake manifold back off and saw how poor a job I did the first time, so I cleaned the faces back up and tried it again, with black Right Stuff this time instead of the grey stuff that came with the gaskets. I also had friends over to lend a hand so we were able to set it straight down lined up perfectly; having lined the coolant channel openings with RTV and putting thread sealer on the bolts this time I’m infinitely more confident in it than my first attempt. The RTV bead looks like a factory job from the outside. I also put in a new thermostat, the old one was looking pretty crusty.

After that was done I put the accessory brackets back on and bolted my new jagsthatrun motor mount adapters to the block, and bolted the mounts to the frame. My initial review is that these are fantastic upgrades over OEM or Energy Suspension mounts - thanks to Harley for the recommendation.

I also picked up some Ryobi screw extractors for the sheared exhaust stud, which to my surprise made quick work of it. I then put in all new studs.

Getting close now - I started swapping in the parts for my R12->R134a conversion, and when I pulled the orifice tube it was mostly black and had metal shavings in it, so I went ahead and picked up a new compressor. Advance Auto had an OEM GM/AC Delco compressor in stock, which was a relief because all the aftermarket/reman comps have terrible reviews. Advice for anyone else doing this conversion, O’Reilly’s has 2 accumulator options - one says R12 and the other says R134a, but the R134a model is for trucks that came with factory R134a - both will work for either refrigerant, but the R134a model would not accept the sensor from my original R12 accumulator, so I returned it and bought the R12 model which was identical to the one I took out. I got that bolted up and new o-rings put in all of the fittings, so all that’s left is putting the switch from my old compressor into the new one.

That brings me here:

(just noticed I forgot to put that idler pulley back on.. gotta do that)

After doing some reading I think I’m going to fab up a block-off plate for the EGR valve, I’m not thrilled about my intake getting pumped full of carbon all the time. Going to just leave the valve on and plugged in to avoid having to get the code flashed out, I have the electronic EGR not the vacuum actuated one.

Once I get home today I’m going to douse it in degreaser and clean it up a bit more, crack open some beers for my friends coming to help, and hopefully have it bolted back in the truck by the end of the night. We’ll see if I manage to get all the wiring right on the first try since I only started labeling halfway into it, sure I’m going to learn my lesson there. Probably going to reloom sections of the harness that have dry rotted and cracked off.

It’s been exhausting but a lot of fun. The most intense job I had done prior to this was the clutch/flywheel and RMS in my 350Z, so lots of new territory for me. I’ll post updates as things progress.