I need help!!!

[tkeduk8r]

Well this is kinda a rant and a prollem... ive been having prollems with my truck overheating, or at least ithink its overheating... ill start out by saying its a 74 i know not a 67-72, but this gets more attention over here than in the 73-87 side of the board.. ANYWAY with that said its a 74 c10 250-6 all stock with no air poiwer steering or brakes... i decided to get the thing ready for an ice cold MN winter by flushing the system and replacing all hoses, thermostat, and belt... NOW the fun part... with the new parts a leak developed in the seam of the drivers side tank on the radiator, plus the flow was not that great... well i took it in to get fixed and it was 70 bux to fix or 105 for a new one.. well i went with the new one and went home to install it... put it in... at this time i also decided to install a set of gauges instead of the idiot lights since i had the garage warm... with that done i started it up to check everthing out... well the temp gauge pegs at 250 (and i put a new acdelco temp sensor in too) and everthing ran ok i think witht eh idiot lights in.... soooo... i decided to pull the new 195 deg thermostat and return it to get another 195 one.. installed it and same thing and now the waterpump is leakin... SO off to get a new waterpump... this time before intalling the thermostat i boiled them on the stove to notice that the original 192 deg thermostat i pulled open alot further than the new 195.... so i put the old thermostat back in and ran it... well it never really got warm and the gauge read less than 175 and i had little or no heat int he cab... sooooooooo of to the parts store again and i got a delco 195 thermostat again, went home and boiled it to check it first.. it opened a little further than the partsmaster 195.. so i installed it.... now the gauge pegged at 250+ again... and i wasnt getting much flow throught the radiator again... UNREAL... so i called an old radiator guy here in town and he said to check the gauge by placing a candy thermometer int eh radiator to chack the temp of the flow.. and i only got 110 max temp doing that...SO i changed the gauge in the cab, and decided to put the old thermostat back in to check the flow temp with that....WELL gauge went in ok but wen i torqued the thermostat housing the threads stripped out of the aluminum housing....SO int he end time to put it away till tomorrow and go get a helicoil kit to put in..... AAAAARRRRRGGGGHHHHHHHHHHHHHHH... anybody have any thing like this unique overheating prollem happen to them???? and can i put a helicoil in a straight through hole???? ive only ever put them in small engine blocks with drilled holes that are not all the way through.... I had to put it awy tonight though, cuz it is becoming a avalance of bad sh**.... any help please...
--mike

[Gee_Emm]

All I can say is good luck and the only help I can offer is bumping this to the top :P

[mikep]

I had the same problem in my boat. Turned out the water pump seal was shot and the pump was cavitating. Changed the pump and it cooled fine afterward. It never leaked a drop.

[stelth2002]

The sensor that you installed is still one made fot the idiot lights. Happened to a friend once. You need to order a special "gauge" version of the sensor. Wish I could help you out. Your engine isn't overheating, it only the sensor.

[mikep]

oops ... missed that part. Yep ...sensor

[tkeduk8r]

thanks people... tok alot to calm me down lastnight, but appreciate teh responses... well im plannin on heading out to the yard here in bout an hour to get another thermostat to block manifold? (on the inline the cast piece the thermostat rests in) and i will douible check the delco part number on the sensor with the parts place... the only kicker bout the sensor is that the gauge seems to read about right with the old ****ty thermostat heating to only 150 degrees or so.... but i will double check.... thanks again fo rthe advice and ill fill everyone in the the result and remedy (cross fingers) so no one else hads to go through this same bs....
--mike

[tkeduk8r]

well i messed around with this thing again yesterday... I double checked witht theparts house on teh sensor and it IS the correct one for the analog gauge not hte idiot light.. so thats done unless the sensor is bad... i installed ANOTHER thermostat after boiling it to check it and ran it last night, but the guauge was still pegging out, even after i swaped gauges inteh cab too...and the gauge will rise slowly as if it is heating normailly it just vever stops rising.. BUT i did hear some noise comin from the water pump area and i wanst gettin any flow this time, and when i shut the engine it started to heat down the return hose from the water pump and hot water started slowing through the upper hose too.... so my suspicion now is the water pump like mikep said.... andif this doesnt fix it it is goint o the radiator shop.... ill keep you all updated...
--mike

[Southpa]

Mike, I went thru a similar experience recently w/ my 350. Just sitting there scratching my head wondering if my truck REALLY IS overheating or if the gauge was bad or whether or not I was using the right sensor etc. etc.

First off, I don't trust electrical sensor/gauges on these old trucks. If you have any grounding problems ie. engine block to frame then your temp. reading might not be right. Thats how they run, the sensor is a variable resistance unit that lets more power to the gauge (resistance goes down) as the truck heats up. But the current has to go the round-about way to complete the circuit.

Your best bet to get accurate temp. readings is to buy a mechanical temp. gauge and sensor. They come as a complete unit all connected up. All you have to do is run the sensor w/ wire thru your firewall and screw it into the block, then mount your gauge somewhere.

[lukecp]

I agree with Southpa....get a mechanical guage. You can pick one up for about $15, it will be very accurate, and they continue to work even if the engine isn't running.

[tkeduk8r]

guys thanks for the insight... i do know however that the engine IS overheating as when i shut the motor off fluid is boiling outboth upper and lower hoses into the radiator and the thermostat housing is hot as a griddle, checked with a thermometer at over 250 degrees... and im not gettting any flow or very little at that high temp... now i have put my old thermostat back in and wallaa its up to bout 175 on the gauge and plenty of flow, but now luke warm heat in the cab.... so I am takin it in firstthing in the morning to have the radiator shop that sold me the radiator to take a peek at it... ill give everyone an update soon as i can... thanks again, you guys are great!!!!
--mike

[rusty ol' 69']

Southpa's right when the guage jams up on the hot side like that it's grounding out on something. Check your wiring for open wounds that are grounding out on the body or exhaust. It also sounds like you got a water pump issue as well. I don't know if you did this but when you put the new radiator in did you fire it up with the radiator cap off to let it bleed out? If not that might be it and it's causing your water pump to gulp so to speak.

[rusty ol' 69']

Alright I read the rest of the posts. Sounds like you have air trapped in your system. Just mho.

[1971LT1SWBPOSI373]

Here's a real curve ball for ya (and I grew up in Foley MN). Maybe your old thermostat is working OK.... is the water in your radiator warming up a considerable amount like if everything was working OK? If you had problems with your radiator (and specifically circulation problems) I wouldn't be a bit suprised if you found a partially or almost completely plugged heater core. And, if anyone in the past has ever put something into your radiator such as "Stop-Leak" you can just about expect to find a problem. I had a Radiator problem on my "Foley" '72, and would up getting the radiator cooked out, and replacing the heater core as well. Haven't had any problems since tho. As for the intake manifold, I would try a heli-coil, and then install studs and LEAVE THEM IN. The more you keep wrenching on bolts the better your odds are on doing some damage. TJ

[tkeduk8r]

well thanks again for the input....

Rusty, on when i installed the new rad i did leave teh cap off to make sure i was getting flow and lett the air bleed itself out, and the flow through the whole system is excellent woth the old thermostat in and without one.... just with the newer thermostats do i not get any flow or little, acts just like the therm is not opening up....

as for the grounding issue i redid the ground strap and checked the continuity both cold and hot to make sure i was grounded ok.... and i should say the gauge doesnt peg all the way out hot just stays at 250, if i ground out the gauge the needle swings all the way down to 6 oclock position, and would go further if it could....

TJ... the heater core has good flow through it as well and i donot believe it is plugged at all jusging by the velocity that it will cool off once the old thermostat opens all the way.. after it oopens the heat is luke warm by the floor as well at the antifreeze in the radiator... oh and i live in sauk rapids!!! do alot of my junkyardin at Golden Spike....

thanks again fellas... keep the brainstorming comin, im up for any ideas other than buy a f***...
mike

[1971LT1SWBPOSI373]

Well............. if your getting your stuff from around the Golden Spike then that might be part of the problem.....

Are you sure that new thermostat is the correct one??? Only use the good stuff and none of that Roberts junk. Personally......... I bought a "high-flow" stat from summit racing just to keep the beast cool. Any speed shop should have one.

Good flow through the heater core is a good sign, but still is not to say that it isn't plugged. If your getting warm air maybe your only getting coolant flowing through a few of the passages. My heater will cook me out of the truck and make my feet hot. Hope this helps. TJ

[tkeduk8r]

well problem all but solved... I took the truck intoday to get the pros to scope it out and htey said all good, they made sure it wasnt overheating, andit is running at the correct 195 degree mark, but the gauge is reading a consistent 60 deg high... So i went and bought a napa sending unit to compare with the delco.. I installed it and same thing.... SOOOO i took the other tempgauge i have and wired it up to the bat and sender in the engine compartment, andit reads just as high... soo it looks like everything is solved cept that the gauges read high.. good ol gm technology i guess... y next step is to borrow a potentiometer from the elec lab where i sub, run itinseries with the gauge, ajust it till gauge reads correct, then take resistance measuremnt of the pot and go to radio shack and get the closest resistor value possible and install in series with the sending unit.... BUT at least this nightmare is over... thanks alot for the help once again, guess htats what the shps are in business for...
--mike