Overheating- WTF?

[Malibob]

Last year I had some problems overheating and decided t start replacing stuff. Fist was a thermostat, second waterpump and belt and then hoses last thing was the stock style radiator in the winter.

So I have been running the plss off of my truck this year and one day she started overheating. Babied her home and filled her up. Now it is becoming more and more frequent. The coolant came out dark purple and is foamy. First off, how many LBS. cap should I be using, secondly what degree thermostat? Is this the reason I keep purging coolant?

Oh also everytime I fill her back up I try to burp it with the heater open too.

Ideas welcome.

[protrash64]

I would ask these questions first: What engine size? Electric or mechanical fan? Radiator type and/or shroud?

Have you checked your oil? Is it foamy like a milkshake? Possible blown head gasket?

[Malibob]

Wow lightning quick response.

283 w/ mech. fan and shroud
original style rad (brass)
checked the oil no foam

[protrash64]

Well, I am no expert by any means.....but generally my radiator caps are 15lbs. I think that is usually standard. Out here in the desert everyone usually runs a 180* t-stat.

Does your fan have a clutch? If so is it bad?

The purple coolant being foamy does not sound good to me. I'm only speculating, but perhaps a head gasket or intake leaking. Is your exhaust putting out white smoke? This indicates coolant in the combustion chamber.

[Malibob]

Not white. Gray sometimes going down the highway when I coast then hit it.
On start up sometimes if I nail it I get some white.

[aerotruk63]

So your engine oil is clear?

[Malibob]

Black, got to change it

not a milk shake though- not frothy

[neto]

I would check compression to see if you have even compression i all cylinders to check the head gasket. Does it heat up while driving on the freeway? if so check your radiator or the lower radiator hose for collapse. If at idle then your fan or water pump. The foamy stuff is strange. I agree with the others, head gasket or intake gasket. Good luck.

[CenValyCali]

Following along because mine overheats at idle. Changed over the water pump and it still gets hot. I've got a electric fan on it now but I think i'm going to go with a mechanical. Can I still use the Mech for supplement on the other side of the radiator?

[andyh1956]

sounds to me like you have compression in the cooling system that is displacing coolant. what to do is drain all antifreeze out & flush & refill with clear water. then go to a truck supply store like truck pro or may even find on line an aditive that you pour into the coolant, forget the name. it will change the cooler of the coolant to, i think a purple color if there is evidence of carbon monoxide in the coolant. i also have a clear tube extension at home that screws onto the radiator filler in place of the cap so i can see bubbles. if i was at home i would go look on the package & get the name but this is all i can do for now. if it changes color then it's teardown time. hope this helps.
andy

[6863m]

I have a 62 and I have put a 350 in from a late 70's van and when I took the old 71 camero 350 engine out it had a shroud but it was a real hokey installation. And from what I can research there is not a good fitting shroud for the 62. So my plan is to use the electric fans and the truck will ultimately live in the Pacific Northwest.

[markeb01]

One other consideration - if you have an automatic transmission and the cooler lines are connected to the radiator, check the transmission dipstick for coolant contamination. If the trans cooler in the lower tank leaks it can toast the transmission.

[jonzcustomshop]

my sisters 78 camaro, and my 83 suburban (350's)both had this problem:
a hairline crack in the cylinder head in the combustion chamber. It was between the exhaust and intake valves, and would only give problems as the vehicles operating temp got hotter.the crack was to the water jacket, so they would burn off water in the cylinder, and you would see a little steam out the exhaust, but no water in the oil.
I don't remember how e found out about my sisters car, but my suburban probably was run with the crack for a few years before it got bad enough to cause a massive cooling system failure under load....
I think the inital crack(s) occured a few years earlier when I had a stuck thermostat in -60 temps, and drove it anyway! just a few miles , but the temp gauge got up to 275-300!!!

[Malibob]

Well lot of ideas here. I am going to do a compression test this week and then correct my timing. If cracked head (which I am leaning towards) then time for a new motor. I will yank this one and finally rebuild an engine. Thanks for the input guys.

[WRO44]

This interests me as well. My truck gets pretty hot while sitting at traffic lights... ie 210-230 degrees. I am running an electric fan. Would it help to have the mech fan on it as well?? Or am I dealing with a bigger issue?

[neto]

I would bet that the radiator is not big enough (row wise) or it's plugged.

[WRO44]

Originally Posted by neto

I would bet that the radiator is not big enough (row wise) or it's plugged.

Is there anyway I can check to see if the radiator is plugged?

[stsalvage]

I could never under stand why any one would be able to blow a head gasket in these old chevy engine.First off you never remove the thermostat.Its the one thing that keeps your truck cool.One other thing I live in Calif. I have a 1965 3/4 ton.I have over 550,000 miles on my engine.I've owned this truck for 16 years and its been in are family form 1969.It was Known as a trash truck we used it to take loads up to the dump.When i got it It had a 307 in it that had been in there sence 1972.It died on me 1 year later.I bought one from a re-builder and its a 355 30 over 260 Horse power.My truck has a 2 speed power glide with a 410 rear gear .The first thing i did when i stated using it as a scrap truck i earned enough money to Buy a new heater core and blower and hoses and changed it my self.Next I had a flex fan that came on the 307 and lucky for me the hood was down when it came apart and 2 blades went throw the hood and cut the top Hose.I found a 1968 ford 7 blade fan blade and bought a clutch fan for it. the next thing i did i found a shroud and that made a big difference.then Came a new radiator a factory one that fit the truck.I had to change the water pump 4 time cus the bearing went out.


Now this is lesson ONE if you have a temp Gauge and its getting Hot Turn on the Heater.

You fry or the truck fry's. Me i'm not one to walk in 103 temp so I don't mind opening the vent wing and put my setting on defrost and blow it out the passenger window.

Open the Air vent By your legs and it will keep you a little more cooler

Now remember the more you pull that Hot water away from the engine like 35 seconds that water going throw that little radiator will cool down water at 220 to 180 in 35 seconds and if you Have a auto matic Run at second trans cooler in front of the radiator

One other thing you might want to buy Get a 13 pound Radiator Cap 16 pounds is to much for these old trucks .

one last thing have a over flow Bottle for the radiator it helps when it want to push the water out as soon as the truck cools down it will suck it back in.

and if you want to Know why i use a ford Factory fan Blade cus chevy dose not make a 8 blade Fan that is really good and pulling the air throw the radiator.

If your going to drive this truck and make money with it make sure you give it as much as you take from it

In all my 16 years for using this as a scrap hauling trailer I've only lost 1 hose cus it got old this is my baby and its bought me every thing i own It has 1972 front disc brakes Power brakes power steering on the frame and i'm running Motor home tires that Cost me 1000.00 every 5 years i get 285,000 mile out of these 10 ply tires 233/85/16 done a lot of up dates to this truck But it make me over 50,000 doller a year take home

[Malibob]

I am hoping mine is just a head gasket. I pulled the valve covers off yesterday and they had what looked and felt like peanut butter in them. So tonight I take the heads off and replace the gaskets. Woo-hoo.

[jonzcustomshop]

Originally Posted by Malibob

I am hoping mine is just a head gasket. I pulled the valve covers off yesterday and they had what looked and felt like peanut butter in them. So tonight I take the heads off and replace the gaskets. Woo-hoo.

It is so easy to type that...big job!
hope that is what it is.
while you have the heads off inspect them in the combustion chamber for cracks, the ones I found on my sub were around the exhaust port, and inbetween the exhaust and intake... same cylinder on both sides went btw..

[Malibob]

Should I hit everything with some sort of cleaner? Brake parts cleaner or something when they are off, to de-gunk everything or will that cause more problems down the road?

[Malibob]

okay passenger side is off and the gasket is all in one piece. Also, that is wher I thought the problem was. So drivers side tomorow. If that one is all in one piece do I assume cracked heads?

[lakeroadster]

Originally Posted by Malibob

okay passenger side is off and the gasket is all in one piece. Also, that is wher I thought the problem was. So drivers side tomorow. If that one is all in one piece do I assume cracked heads?

Seems like if both head gaskets are OK you could get the heads magnafluxed. If they are ok then you have eliminated them as the problem?

[Oklahoma]

I have been having pretty much the same problem ever since my rebuild. I have a rebuilt motor, new radiator, new water pump, new electric fan, added water wetter, changed out t-stats from 165 to 190, 180 seems to be the best, and still running around 110-125, and if i let it sit and idel it will hit the 150 mark before i shut it down, the radiator is a 3 core all aluminum. I am also running AC. just for kicks the other day (when it was 100 deg's out) I turned off the AC, rolled down the windows and turned on the heater, it helped a little, untill i had to stop and the temp started climbing again. I just dont get it, I have a 95 camaro with 200k on it and you cant even make it run hot. It suck's dumping all this money into a vehicle and you cant even enjoy it on the hot days, that's why I put in the AC in the first place.

[protrash64]

Oklahoma.....150*????? Thats not even hot; do you mean 250*??