Inherited '85 C10, need some help

[85_C10]

I recently inherited an 85 C10 Silverado that belonged to my grandfather. It sat up for a few years and my grandmother gave it to me. Now I'm working on getting it back on the road. It has the 305 and a TH350 transmission. I just have a few issues that I need some advice on.

It runs very well which is a good starting point. It sat for a few years because of a transmission leak which would cause the transmission to slip if enough fluid leaked out. I fixed this by replacing the pan gasket. I also replaced a leaky lower radiator hose.

Now for my current issues. When I put the truck in gear it feels like something is holding it back. I feel like I have to give it more gas and rev the engine up higher than I should have to in order for it to get moving. The best way to describe it is that it feels like I'm pulling another truck behind me. I haven't taken it out on the road or anything because I can tell something isn't quite right. It almost feels like something is hanging up. I pulled it down my driveway and back and when I let off the gas the truck came to a pretty quick stop rather than continuing to coast.

The next issue is a horrible squealing/squeaking noise that occurs for the first 20 seconds or so after I start the engine. It's clearly coming from the area of the belts but I can't see anything seizing up. It stops after 20-30 seconds but occasionally does it again if I put the truck in gear and hit the gas.

The last issue is that it doesn't seem to want to warm up to operating temperature. After running for 10-15min the temp needle is barely to the first mark on the gauge. And this is in hot summer weather. The truck doesn't overheat and the water pump is working. There shouldn't be any air in the system because I made sure to check for that after changing the lower rad hose.

Any help is appreciated! I can't wait to get this beauty back on the road. I'd imagine most of these issues are from the truck sitting up.

[VileZambonie]

Did you check the brakes? Sounds like they are hanging up and after sitting I would advise going through them thoroughly.

Replace the belts and make sure everything spins freely.

Replace the thermostat, tune it up, run some fresh gas through it and drive it! Congrats a nice inheritance.

[85_C10]

Thanks for the info.

I went out and jacked up the front and rear of the truck and all of the wheels turned freely. So it appears that none of the brakes are dragging and none of the wheels are seized up. Any ideas? When I put the truck in drive it will creep forward just a tiny bit on level ground. To get it to actually move it seems like I have to give it a lot more than just a light tap on the pedal.

Also, on the cooling issue the radiator fan seems to run constantly from the time I turn the engine on to the time I turn it off.

[frankentruck79]

Parking brake not disengaging all the way?


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[85_C10]

I don't think that's it, I didn't notice any resistance when I jacked it up and spun the wheels by hand. They'd continue to spin freely for a few more revolutions.

Would something with the engine or trans cause this sort of thing?

[haroldwca]

Nice truck !  Exactly like mine, except mine is in desperate need of a paint job.  It's already been suggested and debunked, but my first guess for the lack of pickup from your pickup was a seized parking brake cable.  However, your primary problem may be caused by what left the truck sitting in the first place - leaking transmission fluid.  Did you top it off when you replaced the pan gasket?  It may be that you already know, but you must check the fluid with the engine running.  If not, you get an artificially high reading.  Starting the engine causes the transmission pump to fill the torque converter with fluid - fluid from the pan.  In other words, if you check the transmission fluid with the engine off and it reads full, you are actually quite low on fluid - low enough to cause the transmission to be slipping as you attempt to accelerate.

As for the lack of engine temperature, your thermostat may have been removed at sometime in the past.  Because it is below the top of the coolant level, it is a little inconvenient to remove the thermostat housing to check.  Drain the radiator down about half way to keep from flooding the top of your engine with coolant.  By the way, unlike more modern vehicles, your fan is not electric, but belt driven.  This means it will be rotating the entire time the engine is running.  (I'm assuming a completely factory stock setup.)

Belt squeal can be verified by spraying WD-40 on one belt at a time as the engine runs until the squeal disappears.  It's not a permanent fix - you have merely identified the belt that needs to be replaced.  Good luck and let us know how it goes!

[gezn2]

Yours looks much prettier than mine
I'll second haroldwca, belts will age faster with disuse and may look fine but still slip, the alternator belt on mine is always the first to squeal.
Thermostats also age out, you might well have one that has failed 'open', don't cheap out on the new one because lots of the 'offshored' ones are bad in the box
Your 'lagging' symptoms sound very much like a leaky TH350 I used to live with, to get an accurate dipstick reading the transmission needs to be warmed up to operating temp and shifted through the gears then checked in 'Park" with the engine running. How is the lube in the rear axle?

[85_C10]

Truck seems to move fine now that I added a little more trans fluid. I took each belt off one at a time then cranked the truck until the squealing stopped. Turns out it was the alternator belt. It seemed tight enough to me but I tightened it up a little more and the squealing seems to have stopped. The truck seems to run better when it's in gear after doing this. Don't know if that loose belt was making it bog down a little as it slipped or what but it seems to be doing alright now.

Still need to change out the thermostat.

I'm sure I'll have some other questions as I test the truck out some more.

[85_C10]

Did some more work on the truck yesterday and today. I replaced the thermostat and that seems to have fixed the issue with the truck not warming up. I inspected the old one and it was definitely stuck partially open. I also replaced the fuel filter and air filter while I had the airbox moved out of the way. I also changed the oil.

Two more things, I noticed a nice wisp of smoke on the passenger side of the engine from the exhaust manifold when the truck is running and after I turn it off. I'm thinking it may be a valve cover gasket. Any recommendations for fixing this?

Also, I seem to have some dieseling going on. If I run the engine until it's totally warmed up and then shut it off it will diesel for 10-15 seconds after shutdown. Any ideas on this one?

Thanks for the help so far everyone. Looking forward to getting this truck back on the road. 

[haroldwca]

Kudos for sorting out the issues you've had!  Valve cover gaskets are replaced by removing the perimeter bolts for each valve cover.   The EGR valve may impede easy removal of the passenger side valve cover.  It's removal poses no significant problem - just remove a couple of bolts, then the valve cover will lift right off.  Scraping off the old gasket material may be the toughest part of this repair.  Just about everything has been used as a removal tool (although not everything is recommended).  A gasket scraper is the best idea, but flathead screwdrivers are commonly used. Just be careful that you don't scrape toward the hand that's holding the valve cover. The valve cover gaskets you buy may be of the cork type or the more flexible rubber type.  In the old days, people used RTV sealer to hold cork valve cover gaskets in place during re-installation.  The last time I removed my valve covers, I used the rubber type of gasket, and if I remember correctly they did not require RTV. 

There are a number of causes for dieseling, and often it's a combination that causes this condition.  Of the items that can be addressed by simple adjustment, timing and idle mixture are the two most likely items to consider.  I would check the timing first.  If you don't already own a timing light and a vacuum gauge, I would purchase one of each of these useful (and relatively inexpensive) items for maintenance of your new "old" ride. 

I don't know your age, but anyone under 30 likely has had little experience working on vehicles that have a carburetor and an old-school distributor.  The vacuum gauge is used to adjust the carburetor's idle mixture.  As I say this, it just occurred to me that if you have the original carburetor, the idle mixture screws are probably capped.  They can be removed, but they are pressed in so they must be removed with a bit of force and it requires removal of the carburetor from the intake manifold.

Also let me throw this idea out there.  A basic visual inspection is always a good practice periodically, as well as when doing diagnostics.  On a truck of this age the vacuum hoses (flexible rubber) may have dry-rotted, and the vacuum lines (semi-rigid plastic, and much smaller than hoses) may be very brittle.  They may snap with the slightest bump.  If any of these hoses or lines are not intact, problems will result.

Keep up the good work as you put your Grandfather's old truck back on the road.

[gezn2]

Did some more work on the truck yesterday and today. I replaced the thermostat and that seems to have fixed the issue with the truck not warming up. I inspected the old one and it was definitely stuck partially open. I also replaced the fuel filter and air filter while I had the airbox moved out of the way. I also changed the oil.

Two more things, I noticed a nice wisp of smoke on the passenger side of the engine from the exhaust manifold when the truck is running and after I turn it off. I'm thinking it may be a valve cover gasket. Any recommendations for fixing this?

Also, I seem to have some dieseling going on. If I run the engine until it's totally warmed up and then shut it off it will diesel for 10-15 seconds after shutdown. Any ideas on this one?

Thanks for the help so far everyone. Looking forward to getting this truck back on the road. 

You're on your way
<snippage>
While I was writing a long reply haroldwca posted one covering all the high points and better written than mine. 
Some versions of the carb came with a solenoid to hold the throttle butterfly closed and prevent 'run on', diagnosis might take a while by text   
 

[blazer74]

Do you have fresh gas?
Do you have a high idle?


Causes of running on


Running-on occurs when the fuel/air mixture in the cylinders ignites without a spark. This is known as the dieselling effect because it is caused by the fuel igniting spontaneously in the combustion chambers, which is what occurs (deliberately) in a diesel engine. There are several causes.



Running-on is not good for your engine and it can cause serious damage if you allow it to go on for too long. A stop-gap measure (if your car is manual) is to put the car into gear and stall the engine; but this doesn't solve the problem in the long term.

There are a number of reasons for the engine developing a hot-spot that leads to running-on, some of which are easy to check and cure, while others are more difficult.

The simplest causes are that the wrong grade of petrol is being used (usually of too low octane), the spark plugs are faulty or of the wrong grade, the carburettor is badly out of tune, or the ignition timing is faulty. You should check all these before going on to consider more serious causes such as excessive carbon build-up.

[85_C10]

I'll see what I can do about getting the tools for timing adjustment. To answer a few questions, it does have fresh gas. I can't really tell if the idle is high or not. There's definitely a noticeable drop in RPM when I shift into gear. The RPMs go back up when I put it back in park. Seems like it may be a little high but it doesn't sound excessively high if that makes sense.

Before the truck was parked and sat up I know for sure that it had no issues with run-on. So with that in mind I would imagine that whatever is causing this is something that happened as a result of the truck sitting. Will definitely check out vacuum lines since I know those can go bad from sitting.

Carburetors are definitely before my time! I'm 24 and the oldest cars I've worked on were early 90s models. Does anyone have a good link to a crash course on timing adjustment with on a 305? That's assuming it's not caused by something else.