GMC Sierra 1500 Pick-up

2007 GMC Sierra 1500 Pick-up Heating / Cooling System   

hello,the heater is blowing cold air,the water pump is working,top rad hose is hot,1 inch hose to heater core and back to rad is warm and circulating ,the hose from core to engine block is hot.yesterday i heard a girgle sound from core inside cab of truck,the engine was running,then it started blowing warm air.any ideas?

Are you saying it temporarily started blowing warm air and stopped? The gurgling would seem to indicate air or blockage, although both hoses being hot would not.

Regardless you have one of two problems. Either there is blockage in the heater core or the blend air door actuator is not functioning. Reverse flush the heater core with air or a garden hose to attempt to improve circulation and heat transfer.

I'll assume this is not a 2007 GMC, please confirm the year so I can offer additional instructions on the controls. What you can do in the mean time is start the engine (all noise making accesories Off) and switch the heater control from hot to cool (and vise versa), listen for the blend air door in the heater box... you'll should be able to hear the door open and close.

the pickup is a 1991

Okay listen for blend air door movement, and note if the temperature changes at all when you switch the controller from hot to cold/ etc.

yes, the temperature does go from hot to cold

Are you saying the lever moves OR that you can hear the blend air door appear to fully travel?

as of today feb 12 2008 i had the whole heating system back flushed.it is like haveing a brand new truck,thanks for all your help

Great! I assume you had a complete cooling system flush and fill, this is a good service but often overpriced (isn't everything).

Try it out for a few days and let me know if everything keeps working.

the cost of the flush is 110.02 dollars, cdn,that includes taxes

1998 GMC Sierra 1500 Pick-up Chassis / Suspension & Steering   

My 1998 GMC truck is starting to chase rabbits but only slightly and unexpectantly. I'll be driving along at speed limit and suddenly it feels like i'm riding in a road groove, it'll dart slightly right or left. It's happened enough now, that i know it's somethings up with the steering but i'm unable to pin point what. ?? steering box, pitman arms, tie rod ends?? nothing visible. jacked up the front, wiggled the tires top to bottom and bearings ok. Wiggled side to side and had some play. This GMC has 166,000 mi. Tires good. I could start replaceing everything under there but was hoping that there was a problem piece that you might know about. Thanks

The side to side movement could be in an idler arm,tie rods,ball joints etc.Try this,with the vehicle front end lifted and vehicle supported and the steering column in the lock position,have someone pull in and out at ths side of the front wheel while you veiw these areas.Also look at the steering column coupler.It may be covered by a plastic shield that you can slide up the column.The rubber connector from the shaft to the gear box may be shot.As far as a pitman arm,this is usually a solid arm connected directly to the gear box.The worm gear in the box itself would be suspect here.If youre convinced the wheel bearings are ok,the last items to suspect would be upper and lower control arm bushings and mounts.Let me know of your findings and I'll try and work you thru.
Good Luck,
Paul

Thanks, I'll give that a try and see if i can pinpoint the exact problem. I just hate to start replacing tie rod ends and all the stuff that go with it then find out that it's the steering box. Uhg..

My first check would be in the idler arm and steering coupler then work out from there.
Good luck,
Paul

1998 GMC Sierra 1500 Pick-up Engine   

My trucks check engine comes on and when I check the code its always p0300 or p0302(misfire codes).I`ve changed the plugs,wires,coil and cap.This helped for a short while but the codes re-appear in a few days.This problem has been there for around two years.Any help is greatly appreciated

sorry:its a 4.3 V6

Whats the mileage on the truck, compression test?

IT HAS 190,000 KLM OR ABOUT 118,000 MILES..I`VE NEVER DONE A COMPRESSION TEST

A little high on the mileage, but not bad. A misfire can be caused by the ignition parts that you attended to. It can also be caused by a mechanical problem, a carboned valve slightly sticking or an injector problem.Try running a good injector cleaner through the system with a tank or two of gas.
Spark plug wires usually show themselves when weak, during damp cold weather. If you bought good plug wires, and they are securely attached, they should be fine.
A simple test, with no equipment, can be done. Disconnect the hood light, at night,have a friend start the truck, put into gear with the brake on (putting it under load) carefully observe the wires, trying to watch for a stray spark.
The injector cleaner is probably your best bet.

Thanks:I`ll give that a try.Its only missing when I`m doing between 60 & 70 mph (our freeway speed limit here).I`ll take it in and get the injectors cleaned as well

Sounds like we are going in the right direction. A fuel filter a good idea too.

changed it last week.I`ve ran injector cleaner through it several times but having them cleaned by removing them is still better.I`ll have the compression checked as well.Thanks for your help....Darren

1994 GMC Sierra 1500 Pick-up Engine   

cold starts engine shutters during acceleration,also idles low and rough,after vehicle warms -runs smooth

check temp sensor acts as choke on fuel injection

temp senor took care of the shuttering but the low idle is still rough-but runs smooth out on the road-it like idles smooth and then like something drags it down-then smooth again-

check iac for sticking

1992 GMC Sierra 1500 Pick-up Ignition System   

remove and replace ignition switch

Copy and Paste the following link into your address bar for instructions on ignition switch replacement-

http://www1.autozone.com/az/cds/en_us/[redacted] d/80/08/81/1b/[redacted] 811b/repairInfoPages.htm

Note- Sometimes the lock cylinder (the part that the key goes in) is mistakingly called the ignition switch. The link above also has instructions (right side of page) for lock cylinder replacement if needed.

1992 GMC Sierra 1500 Pick-up Fuel System   

will chug after warming up

When does it chug; on acceleration, cruising speed, when slowing?

Also which engine do you have.

Let me know if the check engine light comes on at anytime while the engine is running.

If a tune-up is overdue it should be done now. New plugs, wires, and fuel filter especially.

1991 GMC Sierra 1500 Pick-up All Part Groups   

ok i wAKE UP AND LEAVE TRUCK CRANKS GREAT DRIVES GREAT TILL WATER GETS WARM THEN ITS SLUGGESH I GIVE IT MORE GAS AND ITS SLOWS JUST FOR A SECOND AND VALVES RATTLE OR SOMTHING LIKE THAT CHECK ENGINE LIGHT COMES ON THEN IT RUNS GOOD IF I STAY IN IT IF I GET OUT OF IT TO LEVEL OUT WITH TRAFFIC IT WILL SLOW BACK DOWN AND IT REPEATS THESE ACTIONS

Sounds like the coolant temp sensor at front of motor.It tells the engine to run a rich mixture while warming up.It appears to be staying rich. An easy fix!

1988 GMC Sierra 1500 Pick-up Ignition System Malfunction When accelerating When warm 

This truck has a 3 speed auto. transmission with a 305 engine.Tha Engine has only 23k
Miles on it after rebuilding. I have had it to a dealer and to several other repair shopps and I have been told that the timing for some unknown reason, is retarding as much as 20 degrees on takeoff from a dead stop. it does this 8 out of 10 times I stop.
The result is very poor powre and sometimes some unkind words from people behind me. The dealer told me to replace the new distributor I already replaced with a Medium duty one. I have not been able to find this part.About the only parts I have not replaced are the 2 injectors tn the throttle body. I understand that I cannot take the spark off the truck computer as there will be no pulses for the fuel injection system. Please can you give me some help? Thanks. Jim S.

Hi;
SOUNDS LIKE THE DISTRIBUTOR MODULE IS ACTING UP. IT IS INSIDE THE DISTRIBUTOR. TRY REPLACING IT AND LET ME KNOW. GOOD LUCK LES. P.S. Did not mean to yell, my caps where locked. Sorry!!!

Sorry, I replaced the Module in the Distributor and the complete distributor,also... the Map sensor the spark timing module and the cold start sensor and the knock sensor. about the only thing I have not tried is the left rear Speaker...Ha Ha...

Hi;
The computer will retard and advance the timing. Have you had a diagnostic test on it?
Might want to see on a scanner to see what the computer is doing to the timing. Good Luck Les.

Yes I have had a diagnostic computer check at two different places, one was the dealer. all they could find was that sometimes when first taking off the spark wants to retard 20 dedrees. and all modules have been changed. We have even ran another ground to a seperate knock sensor not in any connected to the engine block and it still retards. However 2 out of 10 times the silly thing takes off perfect. The computer has also been changed.

Hi;
Try this. Check the centrifugal advance on top of the distributor. If you take the rotor off you will see two counterweights that have springs on them. Make sure they are not sticking. You can do this by manually moving them and they should retract by themself. Thanks Les.

1986 GMC Sierra 1500 Pick-up Interior Components   

i took a huge dump in my pants one day (i thought it was a fart) it stinks so bad that every time i get in the truck and turn on the ac or heater it smells like rotten flesh, iv used every air freshener known to man and nothing works my old lady never wants to ride with me any more what can i do to get rid of the rotten smell of my rectom

Try pouring bleach thru the vent screen on the cowl to try and kill off some of the bacteria in the evaporator housing. You may even plug the drain plug when you do this and drive around a bit to let it slosh around.Don't turn the unit on until you unplug it and allow to drain.It may take a few rinses.Hope your seat survived!

8 ounce OdorXit Magic with Mist Sprayer and spray it into the vent for the heater and air.
Make sure it circulates in the system for at least 30 minutes.
This product is the best on the market to repair your odor problem.
I assure you that it will cure your car of the foul smell for good.
visit the odorxit website to get all the buying information.
I hope this helps

If it were mine I would remove the seat, partially dismantle it and clean thououghly with a commercial carpet / upholstery cleaner.Also clean the catpet and door panels, while you are at it!
If possible leave the windows open an inch for next week.
See a doctor, that should not have happened!

1985 GMC Sierra 1500 Pick-up Heating / Cooling System   

I changed out my heater core and I am attempting to put it back together and I am tring to figure out what postion the heater, defrost doors and the air diverter??? are suppose to be in. This would be the air diverter closest to the core it self which door is open and which way is the diverter faceing and which way sghould it face when it is closed

Hello, Have you removed/replaced the doors from the plenum case? My experience on these is to put the case back in, hook up vacuum to the actuators and finally manually calibrate the temperature control door cable to the temp door. (Normally I wouldn't remove a door fron the case.)

Does this sound like where you are going? I want to help, I just need clarification.

Roger

ok the doors it appears that one door opens and lets air to the defroster and the door to the floor heater is closed then you can open the door to the floor heater and this should close the door to the defroster. are the doors suppose to completely close when transfering over i do understand that I can adjust this after i reinstall the unit know what I really need is which way does the air guide face when the heater or defroster is open and does the heater door help in opening it or closing it p.s. I took the air deflector,guide out it had broken so I had to epoxy it and now I am freezing tell I can get the thing back in Thanks Todd Payne

I know you are counting on me and I want to help. I'll look for an exploded view of the HVAC case.

Do you have a public library near? They may have a reference book that would be useful.

The difficulty I face is not having a sample in front of me to describe to you.

Still trying,

Roger

thanks

I am embarrassed at taking too long. I am not finding what you need.

I'm going to release the question so that others may try. You deserve better service.

Thanks,

Roger

I don't know if you can do it wrong. Won't they actuate when you hook everything up?

I could not find any instructions that suggest needing to 'set' the doors. I have never heard of anyone having to take them back apart.

The links to instructions below seem to be standard for heater core replacement on these.

http://autozone.com/servlet/UiBroker?ForwardPage=/az/cds/en_us/[redacted] d/80/11/54/7[redacted] 5474.jsp

http://autozone.com/servlet/UiBroker?ForwardPage=/az/cds/en_us/[redacted] d/80/11/54/c[redacted] 54c9.jsp