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Overheating..Drawing a blank UPDATE #2

Re: Overheating..Drawing a blank UPDATE Electrical people please read.

The temp sensor sends a resistance value back to the IC...gauge is powered via the IC printed circuit with key voltage...so an voltage problem would effect all the gauges...make sure the engine has more than the one ground strap at the right rear cylinder head..allways makes thing brighter when you add more grounds.

Radiator should have a 10-12 degree drop across the rad with the t-stats open...water pump could be it if the wrong unit was installed as small block serp belts run counter clockwise...i allways had troubles with a/c in town at a light elevating my temp gauge.....the condensor adds alot of heat up front...so adding an electric fan thru a relay triggered via the low psi switch will really help. Also...for shits and grins has the the front end ever been blown out with shop air then had the car wash rinse job...in my line of work i see at least one overheat a day caused by the front end being packed up like someone was growing a small potatoe farm...clean out the cores up front as you will be amazed at the amount of crud that comes out...this manuver is good for dropping temps and head pressure...adding the fan after the cleaning is a very wise choice and in that age range gm made a fan from the factory to go up front...

More later...wife is yelling at me to go for a walk...

DW
 
Re: Overheating..Drawing a blank UPDATE Electrical people please read.

pull the thermostat out and see how it runs
 
Re: Overheating..Drawing a blank UPDATE Electrical people please read.

Had a similar experience with my 86 p/u. I checked everything. Turns out the radiator had rotted inside causing the tubes to close at temp. restricting the flow of coolent. The only way this was found was to take the radiator to a shop and have them disassemble. One other thing, check your coolent for exhaust gases, just because you can't see bubbles, does not mean that you are not getting exhaust into the coolent. Snap-on makes a great kit with the equipment and dye. If I had to guess, I would think that the fins of the condensor and radiator are full of bugs and trash.
 
Re: Overheating..Drawing a blank UPDATE Electrical people please read.

[ QUOTE ]
The temp sensor sends a resistance value back to the IC...gauge is powered via the IC printed circuit with key voltage...so an voltage problem would effect all the gauges...make sure the engine has more than the one ground strap at the right rear cylinder head..allways makes thing brighter when you add more grounds.

Radiator should have a 10-12 degree drop across the rad with the t-stats open...water pump could be it if the wrong unit was installed as small block serp belts run counter clockwise...i allways had troubles with a/c in town at a light elevating my temp gauge.....the condensor adds alot of heat up front...so adding an electric fan thru a relay triggered via the low psi switch will really help. Also...for shits and grins has the the front end ever been blown out with shop air then had the car wash rinse job...in my line of work i see at least one overheat a day caused by the front end being packed up like someone was growing a small potatoe farm...clean out the cores up front as you will be amazed at the amount of crud that comes out...this manuver is good for dropping temps and head pressure...adding the fan after the cleaning is a very wise choice and in that age range gm made a fan from the factory to go up front...

More later...wife is yelling at me to go for a walk...

DW

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Well all the gages are effect I think. It shows more voltage, Temp is up and I think it's showing low on the oil pressure gage. When the llights went bright for a second the Temp gage bounced.

Has electric AUX fan factory. Comes on with A/C or when it see's 220 (according to the factory shop manual). It's on.

Radiator is clear of bugs. It was running warm till yesterday then oll of a sudden running VERY warm.

Let me get this Alternator checked. It might be the whole problem. I'll see if I can throw my spare 60amp on tomorrow night.

Grounds are present and clean but I do plan to add one straight from the battery to the fire wall and the frame. Engine had good ground. Cranks up no problem.

Doug....I hear 134 has more head pressure. When the compressor cyles it's chirping the belt. Belt has plenty of tenssion and is new. Could it be creating that much more drag? Overcharged? The conversion was done by a reputable shop.
 
Re: Overheating..Drawing a blank UPDATE Electrical people please read.

60 amps is enough to float the boat on the burb...maybe on dollar..but not the burb...to many consumers present...

34 does run slightly elevated pressures but nothin astronomical...but in the automotive circles i HIGHLY recommend a big fat helper fan...at an idle cooling goes away without the use of it...semi's don't seem to suffer this problem due to the square inch of the radiator and the us of a air operated fan that takes a good 15 horse to spin under load....so temps of 49 to 55 degree's are possable at idle on days like today...(103 i think here in junction)...also to preserve the frosty air make sure you install a heater shut off valve if not so equipt...which i don't think they do..a vacum operated one is nice tee'd into your fresh air vacum pot...so you haveno hot water recieved to the core when in max air...insulated the outside of the evap box and the suction line and the accumulator is another trick worth the effort...i'm not sure of what compressor that big block runs...mine has a R4..i think yours looked like a sanden from a pic i saw but i'm not sure...if its a sanden its sounds like you might have add on air...is the belt to tight possably...is the clutch slipping...any more info?

DW /forums/images/graemlins/usaflag.gif
 
Re: Overheating..Drawing a blank UPDATE Electrical people please read.

[ QUOTE ]
60 amps is enough to float the boat on the burb...maybe on dollar..but not the burb...to many consumers present...

34 does run slightly elevated pressures but nothin astronomical...but in the automotive circles i HIGHLY recommend a big fat helper fan...at an idle cooling goes away without the use of it...semi's don't seem to suffer this problem due to the square inch of the radiator and the us of a air operated fan that takes a good 15 horse to spin under load....so temps of 49 to 55 degree's are possable at idle on days like today...(103 i think here in junction)...also to preserve the frosty air make sure you install a heater shut off valve if not so equipt...which i don't think they do..a vacum operated one is nice tee'd into your fresh air vacum pot...so you haveno hot water recieved to the core when in max air...insulated the outside of the evap box and the suction line and the accumulator is another trick worth the effort...i'm not sure of what compressor that big block runs...mine has a R4..i think yours looked like a sanden from a pic i saw but i'm not sure...if its a sanden its sounds like you might have add on air...is the belt to tight possably...is the clutch slipping...any more info?

DW /forums/images/graemlins/usaflag.gif

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Yeah it is not a R4 but it is what it was equiped with factory. It has factory dual air and it's on the buld sheet.

The heater coor is not contributing to the over heat. It's more fluid. I have heard the way GM has the heat plumb it does two things.
#1 it equalizes the pressure on both sode os the thermostat so that it can't be held shut by the pressure behind it.

#2 It pre heats the radiator so you don't get a suddend dump of cold that could cause the thermostat to close again.

Those reason make me hesitate to block the flow to the heater core.

Has the factory electric fan that is coming on. I don't hink it's fan since it's running hot at 60-70mph when it has more then enough airflow. 45-50 it does fine.

I'm yanking the Cat for sure this weekend. It's bead style and because of the 8600lb GVWR I'm smog exempt.

As I see it if it's clogging then it's hold heat. Just doesn't seem tho have the amount of air flow out of the tail pipes I would expect, Better the flow out the more heat it's going to carry with it.

I was looking at wrapping the lines for the A/C. I look at doing the blower box as well. Already tinting the windows and actually looking at a confer roof rack as much for hauling bikes but to give some shade on that dark blue roof to help the A/C.

Looks like I'm drinving doallar to work tomorrow. Nice and tosty with high humidity tomorrow. /forums/images/graemlins/rolleyes.gif
 
Ok Rebuilt Alternator on. It was fried! Local shop rebuilt it for $60. Gage never dropped below 13v on the way to work with the A/C off. That's a good sign. Radio noise in CB is gone and need to throw a fese in the car kit for my phone and see if it blows again. I also added a 8 gage Ground wire from battery to fire wall.

Still ran hot and I didn't have on the A/C. I installed a temp gage for the oil yesterday. I hope it's wrong...300degrees on the way to work this morning. /forums/images/graemlins/eek.gif
I think the gage might have a problem...I dropped it a couple times LOL. The oil cooler sure didn't feel like no 300 degrees. So either the gage is bad or the thermostatic valve for the oil cooler is not opening.


Stopping for a real GM cap today.
 
Wheres this "valve" supposed to be for the oil cooler setup? AFAIK, it has a check valve in it (you can hear it rattling if you remove the cooler) but other than that, never heard of any valves in that system except for the filter.

I've got an oil cooler "base" (what the filter screws into) in the garage.
 
[ QUOTE ]
Still ran hot and I didn't have on the A/C. I installed a temp gage for the oil yesterday. I hope it's wrong...300degrees on the way to work this morning.
I think the gage might have a problem...I dropped it a couple times LOL. The oil cooler sure didn't feel like no 300 degrees. So either the gage is bad or the thermostatic valve for the oil cooler is not opening.


[/ QUOTE ]

So if you think your oil temp gauge is incorrect what makes you think your coolant temp is correct? Is that how your measuring the temp? Might want to stick something like a meat thermometer down the radiator on a string with the cap on and verify the cooalant temp. Or hook up a scanner to ECM and see what it says.
 
[ QUOTE ]
Wheres this "valve" supposed to be for the oil cooler setup? AFAIK, it has a check valve in it (you can hear it rattling if you remove the cooler) but other than that, never heard of any valves in that system except for the filter.

I've got an oil cooler "base" (what the filter screws into) in the garage.

[/ QUOTE ]

It's in the adaptor at the block. It's a bimetal spring deal.
 
In my field oil vs water temp generally is a 10 degree difference...generally when the oil is hotter than the water there is a big problem lurking in the pan...whats the oil psi like when she is warm? My rod knocking burb is around 3 psi when warm...and runs a little warm..over 210 when making power at highway speeds..she is on her way out and all i have managed to do with the new motor is to install the crank and build the pistons...to much o/t ava so i'm sucking it up as the 400 is next...really soon...like this week hopefully...doin a ouray run the weekend of the 8/9th with my snap on dealer....would really like to have the chalet ready for duty...

heater core helps the evap from icing over...but in temps over 100 degree's stopping all water to the core has no adverse effect...mine's been that way for years...keeping the 195 is really important with efi though....removing the cat is a good idea....i have found the normal life span of a cat is 10 years before trouble begins...in phx with smog tests its just a trend i picked up on...

DW /forums/images/graemlins/usaflag.gif
 
Seriously Grim, sounds like the fan to me. In fact, sounds like textbook fan problems. If it cools plenty other than when there is a major demand for air and the radiator is clean, it's time to check out the fan.

Not to sound stupid or anything, but the fan is often overlooked.
 
Re: Overheating..Drawing a blank UPDATE Electrical people please read.

When I pulled my Cat. off, it helped several things....

My engine temp stays rock solid, the engine doesn't 'ping' anymore, and it helped the HP a lot!!!!

My 'Burb has 300,000 plus miles on it, compared to your 'cherry.' /forums/images/graemlins/grin.gif
 
[ QUOTE ]
Seriously Grim, sounds like the fan to me. In fact, sounds like textbook fan problems. If it cools plenty other than when there is a major demand for air and the radiator is clean, it's time to check out the fan.

Not to sound stupid or anything, but the fan is often overlooked.

[/ QUOTE ]

Fan is not moving more air then what's coming through the grill at 60mph. It's actully probaly holding things up. Becides the clutch has been replaced and it didn't help.

Exchangingi the oil temp gage today and the cat's coming off.
 
I had a similar problem on my smallblock ElCamino.
When it was idiling in traffic or stuck in a drive-thru it would slowly overheat then puke and die. I changed the clutch, nothing, I pput a heavy duty flex fan without the clutch (bolted directly to the pump, still had the problem (I was running a full shroud also) finally went to electric fans (dual winstar) nooooo problem ever since.
The stock setup should be fine, especially with the 7 blade fan.

Heres a link with some cooling info. Probably stuff you have already seen before but still good for reading.

Cooling Tips
 
ARRGGGGGGGG!!!!!!!!!!!!!!!!!!!!!!!!!

Cat off and no change at idle. /forums/images/graemlins/angryfire.gif
It did bring the temp down on the hwy.

Lot more peppy with the cat off though. Dropped the hammer and lit them up. /forums/images/graemlins/thumb.gif

Well time to have the radiator rodded out. /forums/images/graemlins/tongue.gif

Going to change out the water pump for good measure and flush the block while I have the radiator out. Nobody can tell me a way to ID a reverse from a regular pump without removing it. Not even the dealer parts guy. Hell he didn't even understand the term Reverse rotation pump. He thought that meant it would feed water to the heads first. /forums/images/graemlins/rolleyes.gif

Any good recomendations on water pumps?
 
Re: ARRGGGGGGGG!!!!!!!!!!!!!!!!!!!!!!!!!

Eric,

I had the same issues with the blazer when I added the TPI, tried everything, I ended up being the water pump.

Don't use the factory replacement from the parts store.

I replaced mine with a Milden High Flow Alum one from Summit or arond 70bucks and it resolved the problem, and I replaced my fan clutch with a spring type instead of a liquid type.

It fixed my issues but I'm not sure if it will fix your issue, just my experiences.

Good Luck
Rob
 
[ QUOTE ]
I had a similar problem on my smallblock ElCamino.
When it was idiling in traffic or stuck in a drive-thru it would slowly overheat then puke and die. I changed the clutch, nothing, I pput a heavy duty flex fan without the clutch (bolted directly to the pump, still had the problem (I was running a full shroud also) finally went to electric fans (dual winstar) nooooo problem ever since.
The stock setup should be fine, especially with the 7 blade fan.

Heres a link with some cooling info. Probably stuff you have already seen before but still good for reading.

Cooling Tips

[/ QUOTE ]

That was a good link. I knew most of that stuff before but it was good to read again. The part that really ran a bell is getting the heat out of the engine compartment. With the hood up I'm not over heating. It's only with the hood down. I think tomorrow I will pull the rubber flaps out of the fender wells to give some more places for heat to excape. With the Big block in there it's really cuts off the the space around the frame rails compaired to a small block. I'm also going to lean out the antifreeze mix a little more. I thought I was down around 40% but still near 50/50.

All free stuff worth trying tomorrow. Radiator shop is not open till Monday.
 
Re: ARRGGGGGGGG!!!!!!!!!!!!!!!!!!!!!!!!!

Thanks Rob.

I know the pump on it is not original. I know it was changed last year. The old guy that owned the truck before I bought it didn't drive it much. I don't think he knew it had the problem.

I'll get that pump ordered this week. I'm thinking for putting in a Griffin Aluminum radiator. I don't want ANY more cooling problems out of this thing. Last thing I need it to be hauling that camper and have an issue. Especialy when I head out to AZ next year if all goes well . /forums/images/graemlins/thumb.gif

Hay you got Ralphs number? CLub is on a ride this weekend so nobody local that I know has the number unless the Wiclunds are around. PM it if you can/ I know Ralph has a thermo heat gun. I'd like to check this radiator and see what sort of temps it has.
 
[ QUOTE ]
It's in the adaptor at the block. It's a bimetal spring deal.

[/ QUOTE ]

Have you seen this in a manual or in person? Only "parts" on the adapter in the garage are two spring loaded valves (prolly bypass valves) that at room temperature are very easy to open. There's a plug in one side of the adapter that takes a 3/8" ratchet to pull off, but no clue what that is for...appears to be tied into the "exterior" valve. One valve is right where the filter threads on (dead center) one is off to the side.

Not trying to dilute this thread, just never heard reference to any temperature feature of the cooler setup before.
 
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