rlb
Member
As far as the ATF cooler goes, can someone confirm that the top line at the radiator is the return line to the transmission?
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1994 GMC 2500 5.7l Questions
- Thread starter rlb
- Start date
- Staff
- #22
Yes, those mirrors will bolt on. They are the 88-93 style mirrors, and I believe they are all manual. When I needed one of the style you have, I bought one from a junkyard brand new for about $50. Look on Ebay as you can find a lot of mirror options now for this body style. And for the ATF cooler, I used the B&M kit as it came with hose, fittings, and the cooler. And the top line is the one I tapped into when I last did one. If it does in fact have the 4L60E trans, it is easy to put in a temp sender. There is a 1/8 NPT port on the side for checking line pressure, but it also makes a handy spot to screw in a 1/8 pipe sender for a electric gauge.
Ed HD
Formerly: Dad's 05 LLY
I have a mirror like that I'd let go for cheap. Are they power & heated?
The factory gauge as you know is suspect. It is also affected by grounds and positive voltage. Both connections need to be good. Check fuses for corrosion.
There is nothing wrong with running 20w-50 in a old 350. Cheaper than Lucas. (I sent a 6.5 to the scrapyard with Lucas in it from piston scuffing - I am not impressed with it.) Synthetic oil in this weight is even better. It can help get the last of the life out of the engine.
A good reliability mod is to get the CS-130 alternator replaced with the larger CS-144.
A 454 is going to deliver the same MPG loaded or not. Driven sanely, well, not going to happen with me so that is theory. Others have done so and delivered better MPG with a 454 than a 350 even with the additional power loss in the 4L80E. Absolutely you can suck the fuel down romping it with a 454. A 350 is too small for me and would deliver me worse MPG at a slower speed. A 1994 454 needs help from stock with exhaust etc. but, who is running stock? Loaded a stock 350 is near the same MPG as the 6.5 towing hard. There are some cures to get the 6.5 out ahead in MPG and maybe power. It's too hot and the grades are to steep and long to mess with an undersized engine out here. Absolutely you can build a 350.
:idea: At the end of the day there is still no replacement for displacement. A blower on a 454 Suburban is "fun".
There is nothing wrong with running 20w-50 in a old 350. Cheaper than Lucas. (I sent a 6.5 to the scrapyard with Lucas in it from piston scuffing - I am not impressed with it.) Synthetic oil in this weight is even better. It can help get the last of the life out of the engine.
A good reliability mod is to get the CS-130 alternator replaced with the larger CS-144.
A 454 is going to deliver the same MPG loaded or not. Driven sanely, well, not going to happen with me so that is theory. Others have done so and delivered better MPG with a 454 than a 350 even with the additional power loss in the 4L80E. Absolutely you can suck the fuel down romping it with a 454. A 350 is too small for me and would deliver me worse MPG at a slower speed. A 1994 454 needs help from stock with exhaust etc. but, who is running stock? Loaded a stock 350 is near the same MPG as the 6.5 towing hard. There are some cures to get the 6.5 out ahead in MPG and maybe power. It's too hot and the grades are to steep and long to mess with an undersized engine out here. Absolutely you can build a 350.
:idea: At the end of the day there is still no replacement for displacement. A blower on a 454 Suburban is "fun".
rlb
Member
I like the idea of running a 20-50 better than Lucas or STP. Still I don't know what oil the previous owner put in there, or what the oil pressure really is.
Since I am in NC a heavier weight oil should not be a problem, though we have had some lows in the teens lately. However i'll probably change the oil to a 10-30, get it hot and check the pressure with a mechanical gauge. If its low I might STP it and try 20-50 at the next oil change which should be in the spring.
So we are talking about big blocks and blowers now eh? Lets tone it down a bit, what is the best bang for the buck I can do for some HP on this 350? Right now i'm focused on changing all of the fluids and fixing the little stuff, gotta have it driving well and reliable. But its bone stock. I could at least put a K&N and maybe some headers on there.
Since I am in NC a heavier weight oil should not be a problem, though we have had some lows in the teens lately. However i'll probably change the oil to a 10-30, get it hot and check the pressure with a mechanical gauge. If its low I might STP it and try 20-50 at the next oil change which should be in the spring.
So we are talking about big blocks and blowers now eh? Lets tone it down a bit, what is the best bang for the buck I can do for some HP on this 350? Right now i'm focused on changing all of the fluids and fixing the little stuff, gotta have it driving well and reliable. But its bone stock. I could at least put a K&N and maybe some headers on there.
ak diesel driver
6.5 driver
I went to napa and bought replacement glass for around $15
Seriously if the engine turns out to have oil pressure issues hopping up the power is the last thing it needs. Exhaust is a good place to start although a free flow exhaust affects EGR under high load and causes some spark knock. K&N is a waste of money as they let more air and lots more dirt in than a cheap paper filter. I have had this free flowing dirt a K&N let by ruin a IAC motor and stall the engine at idle. There are other modern aftermarket dryflow filters out there that are a better choice if you have to do an intake or better filter.
rlb
Member
The coolant temp reading on the dash fluctuates between 150 and 210 degrees when driving. It seems to be rather indiscriminate. Looks like the issue was not my thermostat (I replaced it to find the old one looking brand new) but now I suspect the temp sensor itself. I borrowed an IR heat gun yesterday after I replaced the thermostat. Reading 195 degrees right at the temperature sensor on the manifold. 210 degrees on the driver's side head near the temp sensor there. (At the time I took these readings, it was idling after a drive and the temp gauge on the instrument cluster read 150) I read somewhere that the single wire sensor on the head is what is responsible for the reading on the instrument cluster gauge. It looks old, i'll swap it out and clean up the wiring. WarWagon, you will be proud.. I cleaned every ground I could find in the engine compartment yesterday.
The rear heat works well all the time. The front heat is pretty weak. Blend doors seem to work, when I select cool air it blows cool air, hot it blows slightly warm air. It works a little better with some engine RPM's than at idle. I made sure to burp the system after I changed the thermostat, hopefully no air in it. I topped it off, drove around, topped off, drove again and topped off again. Does the heater core have a flow control valve I should look at? I'll diagnose some more today. The hoses going to the front heater core both felt like hot coolant was flowing through them. I might take a temp reading. Maybe the next step is to flush the heater core.
My rear U-Bolts are pretty much toast. Its a 14 bolt. The leaf springs and bushings look good though. Anyone know a good source for replacement u-bolts and the bottom plate that the u-bolt nuts tighten up against. The u-bolts are badly corroded just above the plate.
The rear heat works well all the time. The front heat is pretty weak. Blend doors seem to work, when I select cool air it blows cool air, hot it blows slightly warm air. It works a little better with some engine RPM's than at idle. I made sure to burp the system after I changed the thermostat, hopefully no air in it. I topped it off, drove around, topped off, drove again and topped off again. Does the heater core have a flow control valve I should look at? I'll diagnose some more today. The hoses going to the front heater core both felt like hot coolant was flowing through them. I might take a temp reading. Maybe the next step is to flush the heater core.
My rear U-Bolts are pretty much toast. Its a 14 bolt. The leaf springs and bushings look good though. Anyone know a good source for replacement u-bolts and the bottom plate that the u-bolt nuts tighten up against. The u-bolts are badly corroded just above the plate.
rlb
Member
Test port on the 4L80E is midway above the pan driver's side. Look for the plug on the body - it is hard to see because it is an inch or two from the edge of the pan going inwards.
What condition did the inside of the radiator look like? With this body style you want to remove the grille and then move the oil coolers away from the condenser and clean the mat of buildup off the condenser from behind the oil coolers. Scrubbing bubbles on the radiator and condenser help clean these "air/bug filters" out. How old is the fan clutch - they have a life of 5 years as they loose 200 RPM a year.
With the door noise the front blend door may not be moving enough. The quick connect fitting for the heater has a flow restriction in it. possible it plugged. I would use the temp gun on the heater core pipes to help verify if the heater core is hot or the door isn't moving enough. You can drop the blend door motor off and see if you can gently move the door more in the hot direction. Watch the door in action moving the temp on the control head to know what way to move it.
The gauge temp sensor is on the front driver side head on the side. Replace both the sensor and wire if in doubt - you are verifying it with the temp gun.
If the radiator is ok inside and out suspect a water pump going bad/worn impeller.
rlb
Member
Thanks again for your help.
I drove it to work today (20 miles) and shot the temperatures again. Still 195 at the manifold next to the thermostat, and 210 at the suspect temp gauge on the driver's side head. I'll install a new temperature sensor tonight.
The radiator looks clean inside and I know it has 70,000 miles on it, same with most of the hoses. Can't say how old the water pump is for sure. It does not leak, but its not a shiny new piece that's for sure.
Fan clutch seems to be pulling enough air. I gave it a spin with my hand when the truck was hot and there was an expected amount of resistance. The blades continued on maybe 1/8 turn after I took my hand off of it. Further, when idling I can feel a bunch of air being pulled through the grille. Everything looks clean but I will pull the grille off this weekend and clean it anyway. I have a hayden transmission cooler that I want to install, so i'll investigate that.
In the grille on the passenger side in front of the radiator, it looks like I have an oil cooler (engine oil or transmission? couldn't tell with the grille on) then the AC condenser and behind that is the radiator.
I drove it to work today (20 miles) and shot the temperatures again. Still 195 at the manifold next to the thermostat, and 210 at the suspect temp gauge on the driver's side head. I'll install a new temperature sensor tonight.
The radiator looks clean inside and I know it has 70,000 miles on it, same with most of the hoses. Can't say how old the water pump is for sure. It does not leak, but its not a shiny new piece that's for sure.
Fan clutch seems to be pulling enough air. I gave it a spin with my hand when the truck was hot and there was an expected amount of resistance. The blades continued on maybe 1/8 turn after I took my hand off of it. Further, when idling I can feel a bunch of air being pulled through the grille. Everything looks clean but I will pull the grille off this weekend and clean it anyway. I have a hayden transmission cooler that I want to install, so i'll investigate that.
In the grille on the passenger side in front of the radiator, it looks like I have an oil cooler (engine oil or transmission? couldn't tell with the grille on) then the AC condenser and behind that is the radiator.
rlb
Member
rlb
Member
Unfortunately the temp sensor I bought for the driver's side head - did not fit. Wiring clip was incorrect. I need to get a different one that works with the single wire connector. I'll have to order it.
I did some tests this evening and I am 100% sure the heat output in both the front and rear is significantly affected by engine RPM. Its barely warm at all at idle, if I put it in neutral and rev to 3000rpm, the heat gets nice and toasty. Unless I have an air bubble somewhere in the system, it has to be a bad water pump. Belt is new and well-tensioned. Is there anything special about burping air out of the system? I've driven it around and then topped off the radiator several times since I replaced the t-stat yesterday. Both radiator and the coolant reservoir are full.
I did some tests this evening and I am 100% sure the heat output in both the front and rear is significantly affected by engine RPM. Its barely warm at all at idle, if I put it in neutral and rev to 3000rpm, the heat gets nice and toasty. Unless I have an air bubble somewhere in the system, it has to be a bad water pump. Belt is new and well-tensioned. Is there anything special about burping air out of the system? I've driven it around and then topped off the radiator several times since I replaced the t-stat yesterday. Both radiator and the coolant reservoir are full.
rlb
Member
Anyone know if a universal temperature sender like this one will work.
http://www.oreillyauto.com/site/c/d...ck=Search_N2346_1160312_-1&pt=N2346&ppt=C0331
http://www.oreillyauto.com/site/c/d...ck=Search_N2346_1160312_-1&pt=N2346&ppt=C0331
Short answer: NO!. Get the proper one for the truck ordered in. That is my favorite parts place and they did get one in for the 1995 on mine. Dealer for the parts if they can't get it. This part is too sensitive to mess with anything else.
Opt for the "New" water pump as 1995's had a balance flow issue that would boil over the passenger side bank while the driver side was reading 210. You don't want to get one of these messes in a rebuilt form. One of the few times we took our 1995 350 to the dealer and then found it was a unusual but common to 1995's water pump failure. The diesel's didn't suffer as bad but still had the balance flow issue somewhat.
rlb
Member
Dealer has one in stock. $35, will put it in tonight. If that does not work, i'll probably tackle the water pump on Saturday.
I'm probably limited to whatever AutoZone or CarQuest has for the water pump. I'm guessing if the pump is the same part number as the 96-newer 350its probably the new design?
- Staff
- #37
The 96+ water pump is different from the 87-95 pump. The VORTEC engine started in 96 and is a completely different cooling system design. I put one on from CARQUEST before and had no problems with it, the AZ ones have given me MANY problems though and I refuse to run them anymore.
More or less it was the factory pump that had the defect. A new replacement for your year won't.
Autozone fires "hero" employees for stopping a robbery with their own guns. The parts they sell are also garbage - their warranty doesn't cover a rotor if the pad comes off the backing plate... I don't set foot in AZ anymore.
Autozone fires "hero" employees for stopping a robbery with their own guns. The parts they sell are also garbage - their warranty doesn't cover a rotor if the pad comes off the backing plate... I don't set foot in AZ anymore.
rlb
Member
According to your profile, you're in AZ right now!
I bought a replacement pump from O'Reilly today. It was probably re manufactured. I'll slap it in along with a new coolant temp sensor tonight.
tanman_2006
Just a farm kid...
There are just as many mods for a TBI 350 as a 6.5L. Your limiting factor is going to be the weight of the burb and the 4l60. The 4l60 doesnt like abuse, I've had 2 last to atleast 250K and one truck that ate them every 30-40K including cracking cases. The truck with bad luck was the farm mud truck and had its share of abuse.