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78 blazer electrical and engine problems

  #1  
Old 03-22-2010, 04:29 PM
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Default 78 blazer electrical and engine problems

hello everyone. I am new to the forum and recently drove to another state to purchase a 1978 Blazer 2wd v8. I have never owned an older vehicle in my life, I am 25, married, and have been mostly into fast newer sport cars. Well anyways, I want to learn about older motors/transmissions and how to work on them in general. I drove 7 hrs to go look at this blazer and everything worked, power windows/locks/radio. And halfway home the radio just stops making sound. Then about 30 min from home the power lock switch no longer works. Im really angry and feel like I got taken for a little ride. On top of all that I checked the oil this morning after driving the 7 hrs home and there is hardly anything on the dip stick. Can anyone help me with these problems?

At first when the power locks didnt work they made a very tiny machine gun sound that sounded like it came from behind the dash and the locks wouldnt budge. Today when I tried to hit the switch no sound or movement at all. Is there some kind of a circuit breaker or relay that I need to check, if so where is it located?

The radio we can forget about now honestly bc of the oil situation. What kind of oil does a 78 blazer v8 take? And do I put it in the dipstick or in the passenger side valvecover (i think thats what its called). Nothing leaked on my driveway over night, and I dont see any drips forming. Is this anything you guys can help me troubleshoot and fix myself?

And my 3rd and final current problem is that I dont know how to lock the rear NON power tailgate. I can pull the handle out and unroll the window, close it, and roll it back up, but when I insert the door key into the cylinder the whole handle moves and not the lock mechanisim. So now anyone can just get into the blazer whenever they want. What are my options here?

Im sorry for all my issues, I am very active in my Subaru forums from NASIOC to IWSTI and can answer pretty much anything on there. This is my 1st day on here and I want to love this blazer, but it really seems like I got ripped off. Please help me out or steer me in the right direction.
 
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Old 03-22-2010, 05:42 PM
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well the electrical could be many different things. you're gonna need a decent wiring diagram to diagnose. there is only a few other k5 members on here that are active including my self.
 
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Old 03-22-2010, 05:53 PM
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thanks for the help. I really want to drive 7 hrs and punch this dude in the mouth. I even went to autozone to get a haynes manual and it really doesnt show much in the way of wiring. Any help to any of the questions I asked would be greatly appreciated. I will sign up for the other website immediately as well
 
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Old 03-22-2010, 06:30 PM
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haynes wiring sucks IMO, chilton is way better even though haynes makes chilton, i picked a chilton up for mine 2 days ago and it was awesome until it was stolen....
 
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Old 03-22-2010, 10:15 PM
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Wow.. Nice replies there Spectre... Way to even give anyone here a chance... Such a waste.

On the locks, have you checked the fuses in the fuse block under the dash? I know that the newer ones run off of the PWR ACC fuse. There also should be a relay for the locks under the dash. There should be a circuit breaker in each of the lock actuators themselves.

The radio should have a fuse labeled for it. Check that and then check for power at the back of the radio. Its possible that some wires crossed between the two systems and caused both fuses to blow out.

The choice of oil depends on your weather. I run 10w40 in my engine year round, but that is to combat a bit of a pressure problem when up to full operating temperature. 10w30 is what is recommended for most climates. Oil consumption could be caused by either bad rings or bad valve seals. Does the engine smoke at all on start up or when you are going down the road?

It is odd that you would have power locks and not have a power rear tailgate. But your problem sounds like the lock cylinder has either failed or there are some missing components in the lock mechanism. LMCTruck shows what is supposed to be in there on pg 24 of the 73-91 Blazer/Jimmy Catalog and I have also included one out of the factory service manual I have for my '74. It's the same handle used all the way up through.

The problem is, you have to basically remove the crank handle assembly to get at these parts. You can get at the two bolts that hold it onto the tailgate by first removing the access panel on the inside of the tailgate. You then can move the window regulator to allow access to the nuts for the crank handle. There should be one position that allows access to these nuts, but I wasn't able to find that position when I worked on the crank handle on my K5. One word of caution once you get into this, if you crank the window out past 1/2 way, you need to support it on something or you'll bend/break things.

If you want to know pretty much everything there is to know about your truck, get yourself a copy of the factory overhaul manual, service manual, and electrical manual for your truck. They are a wealth of information. I have everything for my '74 including the illustrated parts manual that includes the '78 model year. I then have the factory manuals for '88, '90, and '91.
 
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Old 03-23-2010, 06:55 PM
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Thanks Swartlkk for the helpful info. First I dont have any manuals to tell me which fuses or which so i cant currently check any for the door locks, guess I'm going to buy a Chilton to get my by for the meantime. When I hit the unlock switch now it makes the very tiny machinegun clicking noise near the middle of the dash and a light flickers down there. Is the relay located in the middle of the dash?

I drove it 415 miles home and today I went out and bought some 10w30 like you recommended and had to put in 2 quarts. I had my father come over and scope it out and he seems to think the rear main seal and possibly the front main seal are the cause of the oil leak. Can anyone give me an idea what a shop would charge for doing that?

And something is either not functioning with the tailgate lock or the previous owner slapped a new tailgate on leaving me without a key. Does the LMC catalog or anyone else have the whole assembly for purchase that comes with a new key and I could just bolt it on?

And sorry one more question.....does a typical 78 blazer have a rear seat that folds up to give you more room in the back? I have a seat not bolted in and the holes are carpeted over, no seat belts or anything. The seat I have does not fold. Dont know if its original, but most likely not. Im going to rip out all the indoor outdoor carpet and see if there is any rust. Now that I think about it I'm sure there is rust bc why else would u put in indoor outdoor carpet.

I just need to know if I should cut my loses now and try to sell it or fix all these problems. My father says the motor sounds really good, no oil is getting in the coolant and vice versa, its not smoking as well. But now I'm noticing its all rigged and the previous owner took me for a little ride knowing all the problems it has.

oh.....and the dash says Silverado on it......guessing thats not original either.

I really appreciate the help guys, just have had a ton of this crap frying my brain these past 2 days. MONEY MONEY MONEY
 
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Old 03-23-2010, 07:41 PM
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I'd keep an eye on eBay for a good set of manuals. Here are a few that you might want to jump on:
1978 Light Duty Truck Service Manual - $9.99
78 CHEVY CAR & LIGHT DUTY TRUCK REPAIR+OVERHAUL MANUALS - $35

I couldn't find the wiring manual, but you just have to keep a look out for one.

As far as the door lock relay goes, I would follow the noise and find its source. Then start probing the wiring to see how much voltage there is at various places as well as making sure that when you have a ground, it is a good, strong ground.

The front cover seal is fairly easy. The rear main seal is quite a bit different. Either the engine will need to be pulled or the transmission to repair the rear main seal. That will be $$$. How much depends on the shop and their rates. Rates can vary greatly so you should get a few estimates from trusted shops.

LMC sells a new lock that comes with keys. You may still be able to get a lock cylinder from the dealer and have them code the lock to your front door locks so you don't have to carry another key around with you. Right now my rear window crank is lock-less. I'm not spending money on a lock for it when I have a rust free and fully operational power tailgate to put on once I get the rest of the body work done.

The quick latch seat did not come about until later. You could have a seat with a fold down seat back, but the bottom of the seat would be bolted down. If you wanted people to safely sit back there, you would need to get some seat belts. LMCtruck has those as well, but you can find them at junkyards as well.

As far as whether to cut bait or stick with it, that is up to you. I love my K5 and can't wait until I can get it fixed up like I want. I'm already laying out a fully 4-linked suspension for the 2nd frame I'm going to be getting this spring.
 
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Old 03-27-2010, 11:04 PM
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i cant believe you bought a 2 WHEEL DRIVE 78 blazer that has power everything. Your just asking for problems. Remember this in the future on older cars you want MANUAL EVERYTHING unless you wanna deal with the disaster that old electrical **** is. the only electrical on my 76 and 73 blazer is in the ignition system,audio system and lights. Rolling a window up and down and operating a lock manually is well worth the hassle involved in fixing all that crap. Best of luck in the future as you have quite a bit of tedious work ahead of you now
 
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