Chevy problems (YEAH, I KNOW IT'S NOT A MOPAR)

[sixpack_sid]

I have a '94 Chevy Silverado w/tow package & plow on it. (Now I know this is a MOPAR site, but I have 2 muscle mopar cars & you guys give great answers so I figured I'd ask the experts for any advice!) I don't know if the temp guage works but it's constantly under 100 degrees and doesn't blow any hot air. I did change the thermostat and that didn't help. I've had the truck for 2 years now. It was like this last year and I dealt with it, but I'm freezin my a** off & I need it fixed. Anybody know what could be the problem? Or where to start looking?
Also, the motor was bad when I bought the truck. I got a used 350 motor from the junkyard. It is automatic. When I step on the gas, it hesitates, sometimes it bogs out & seems like it's going to shut off. So I let off the gas & give it gas again-it hesitates. It seems to idle fine. And sometimes when I'm coasting at a lower speed & I'm not on the gas, when I do step on the gas lightly it will buck until I let off the gas or step on it harder. Any ideas on what could be the problem?
--Also, my daughter just bought a '94 S15 GMC Jimmy AT w/push button 4x4. When I tried the 4x4 switch it blinked 3 times but didn't engage. Now it doesn't do anything when I push the button. Any ideas on what could be the problem? I live in the Northeast & NEED 4x4! Any help would be appreciated!

Thanks!

[dukeboy_318]

i assuming the blower works, on my dads sivlerado, we had to replace the heater switch inside the cab cause it stopped working and working turn the air from cold to hot???, could be that, either that or the thermostat you installed is junk too, it does happen occasionally. 

[Back N Black]

Maybe its air locked? try bleeding the system. Feel the lines at the firewall going into the heater core, they should be hot/warm.

[Steve P.]

A few questions.

Do you use this truck in the summer? If so, does if get up to normal temps in warm/hot weather?

Are you completely hooked up to all the 1994 computer wiring or did you scrap all that and just run a carb?




Things to check:

When it is sitting cold, remove the radiator cap and check the fluid level. Top it off if it isn't already.

With the cap still off squeeze the top radiator hose slowly and watch to see if the coolant level rises in the rad.  It should. If not you have much air in the system. Most times I have seen this it is due to the WRONG upper hose being installed and it horse shoes up too high trapping air. This can make the T-stat not work correctly.  The upper hose should be no higher than the upper neck of the rad.

Check the overflow/holding tank. If should be at or just above the cold mark. Top it off if it isn't already.

Still with the cap off the rad.  start the motor and look down into the rad. The coolant should NOT be moving. If it is your T-Stat is stuck open and will need to be replaced.

Reinstall the rad. cap.  Turn on your heat and high speed fan.

Now you need to start feeling the hoses. If memory serves you have a feed coming from the motor going to the heater core and then another hose coming from the core to the rad. near the top. Or maybe it just feeds back to the water pump. Either way you need to continually feel each of these hoses. One should get warm rather soon and then the other shortly after.  Also feel the upper rad. hose frequently. It should go from cold, cold, cold, to hot. That will tell you when the T-Stat opens. This takes a few minutes.  When the T-Stat opens that means the motor is up to what ever temp the stat is set for. At that time the heater core hoses SHOULD be both rather hot.

Things that CAN be the problem:

1) Low coolant/anti-freeze.
2) Bad T-Stat.
3) Plugged heater core
4) Bad heater/A/C control head
5) Vacuum leak causing control head problem. (If vacuum operated). Raises my brow due to the truck running badly.

Can also be a combination of some of these.

Because you say the gauge stays under 100* and you are freeze your butt off I am thinking low coolant and/or bad T-Stat. That is why I asked if you drive this truck in the hot months.

Let us know..

[no318]

The Jimmy 4x4:

  Uses a vacuum actuator with a cable (like a cruise servo.) to engage the front axle.  Depending on wheter it is push button/auto. 4x4 or manual lever 4x4 the transfer case is engaged with a motor or the lever.  It sounds like the AXLE is not getting engaged.  Vacuum goes from the engine to a switch on the transfer case.  When engaged, the switch allows vacuum to the actuator (under the battery tray if I recall), which pulls the cable to engage the front axle.  Check for vacuum leak(s) and or the switch.  You can test the actuator with a vacuum pump and see if the light stays on.   Hope my reply is not too confusing.

[sixpack_sid]

A few questions.

Do you use this truck in the summer? If so, does if get up to normal temps in warm/hot weather?

Are you completely hooked up to all the 1994 computer wiring or did you scrap all that and just run a carb?




Things to check:

When it is sitting cold, remove the radiator cap and check the fluid level. Top it off if it isn't already.

With the cap still off squeeze the top radiator hose slowly and watch to see if the coolant level rises in the rad.  It should. If not you have much air in the system. Most times I have seen this it is due to the WRONG upper hose being installed and it horse shoes up too high trapping air. This can make the T-stat not work correctly.  The upper hose should be no higher than the upper neck of the rad.

Check the overflow/holding tank. If should be at or just above the cold mark. Top it off if it isn't already.

Still with the cap off the rad.  start the motor and look down into the rad. The coolant should NOT be moving. If it is your T-Stat is stuck open and will need to be replaced.

Reinstall the rad. cap.  Turn on your heat and high speed fan.

Now you need to start feeling the hoses. If memory serves you have a feed coming from the motor going to the heater core and then another hose coming from the core to the rad. near the top. Or maybe it just feeds back to the water pump. Either way you need to continually feel each of these hoses. One should get warm rather soon and then the other shortly after.  Also feel the upper rad. hose frequently. It should go from cold, cold, cold, to hot. That will tell you when the T-Stat opens. This takes a few minutes.  When the T-Stat opens that means the motor is up to what ever temp the stat is set for. At that time the heater core hoses SHOULD be both rather hot.

Things that CAN be the problem:

1) Low coolant/anti-freeze.
2) Bad T-Stat.
3) Plugged heater core
4) Bad heater/A/C control head
5) Vacuum leak causing control head problem. (If vacuum operated). Raises my brow due to the truck running badly.

Can also be a combination of some of these.

Because you say the gauge stays under 100* and you are freeze your butt off I am thinking low coolant and/or bad T-Stat. That is why I asked if you drive this truck in the hot months.

Let us know..

Yes I run it in the summer. I haul lawn equip around w/trailer. Sometimes it plagues pretty bad. But it never runs hot.
I had it running for over 1/2 hr while plowing & felt the hoses-they were cold. I took off the radiator cap and the water was not hot. I could put my finger in it. I followed the heater hoses from the heater core & one runs directly into the radiator & the other one runs into the back of the engine block. On my other Chevys I've owned usually one comes off the water pump & goes in, and the other one comes somewhere off the block. Could this be the problem? Could I correct it by getting a different water pump with an opening for the heater hose?
STILL tired of freezin my a** off!
Thanks for all the help!!

[Muscles]

Hey the problem on you're on the Jimmy could just be a bad switch box.  I would have it checked out.  And on the '94 Silverado, it sounds like a problem with the heater core.

[Steve P.]

Sid, this certainly sounds to me like you are low on anti-freeze. I know you said you could put your finger in it, so the level there is not low, but there is no way you could PLOW for half an hour and not heat up your motor.

The gauge says it is below 100*. I believe it is working. (Well, sort of). The water temp sending unit is normally mounted high on the motor. If it is NOT sitting in fluid it will not read correctly.

------  OR  -------   your T-stat is stuck wide open and not letting the motor ever come up to temp. did you start the motor with the rad. cap off and watch for flow? This is an important step... Go back and re-read what I posted earlier and follow the steps. As you see what is going on we can help with the next step.

I did my fair share of plowing just off from Lake Ontario. Both residential and commercial. Trust me, your motor should be making plenty of heat...

PS. the heater core outlet to the rad. is not a problem. There are tens of thousands of those trucks out there making good heat set up just the way yours is.   One thing to look for is a kink in a hose. That will stop  fluid from moving through your core and keeping you from having heat.

[NMike]

are the hoses hooked up properly? i know some chev's have a seperate hose from the rad going to the engine or heater core. i can't remember exactly.

if the hoses are routed wrong, then you could be sending the by-pass hose flow straight to the rad rather then back into the engine.

on the jimmy, check the operation of the shift motor on the front diff. might also be the shift motor in the t-case

[darkfiire5000]

Try checking the blower motor resistor