Boiling over...

Hey guy's, i hope this is in the right section...My father's 89 Scotsdale has been over heating now for a while and we just cant figure out what's wrong with it.

1) We took it and had it flushed...

2) Water pumped was changed last year and is not knocking or making any racket...

3) Thermostat has been changed several times...

4) Had a minor leak before and hoses were replaced, not leaking now...

5) Removed the thermostat and drove without it, as someone suggested and that didn't help...

It's still over heating and bubbling over. What else could it possibly be? One person said it could be a head gasket and that you could buy a product that might close the seal? I'm not sure what to do now. :banghead: I'm trying to get him out of the dump's about it so any advice/help/comments would be greatly appreciated!

Thanks!!

Do you have a mechanical, thermostatic, or electrical fan clutch?
Does the coolant auxiliary coolant tank smell like contaminated fuel, or oil?
Is your coolant auxiliary tank contaminated with rust?
Are you using 50/50 coolant boil over protection?
Is your radiator cap good? a pressurized system will increase the boiling point for boil over protection.
Is there any bugs, or road litter blocking the air flow through the radiator core?

Make sure you are doing a proper coolant bleed procedure, because any shortage of coolant could cause boil over, and lose more coolant.

1) Add 1 Prestone/Peak Coolant flush kit and a little water pressure from a garden hose to purge air from the coolant system.
2) Monitor coolant level in auxiliary coolant tank for any lost coolant in coolant system.
3) Car wash both HVAC condenser core, and radiator core.
4) Test fan clutch

Hey guy's, i hope this is in the right section...My father's 89 Scotsdale has been over heating now for a while and we just cant figure out what's wrong with it.

1) We took it and had it flushed...

2) Water pumped was changed last year and is not knocking or making any racket...

3) Thermostat has been changed several times...

4) Had a minor leak before and hoses were replaced, not leaking now...

5) Removed the thermostat and drove without it, as someone suggested and that didn't help...

It's still over heating and bubbling over. What else could it possibly be? One person said it could be a head gasket and that you could buy a product that might close the seal? I'm not sure what to do now. :banghead: I'm trying to get him out of the dump's about it so any advice/help/comments would be greatly appreciated!

Thanks!!


the head gasket failure with this overheating is common. exhaust gases enter the coolant system. then air bubbles are created. the water pump does not pump this air mixture. then the temp surges.

with the engine running place a plastic sheet as a cover over the radiator pressure opening. rev engine and see if the sheet moves with the exhaust.

looking into the radiator with engine running you should see these air bubbles.

stop leak sometimes will stop/reduce for awhile.

Well thank you very much for the reply, a little more technical then i was prepared for to be honest.

1) Ok, i'm not certain about the fan clutch. Is there a way to easily tell?

2) It doesn't smell of gas or oil to us. Not sure what the "auxiliary tank" is or where it's located but i'm determined to find out!

3) I believe there was some rust debri at some point before it was flushed but we havn't seen much.

4) I havn't heard of "boil over protection" so i highly doubt it's been used. We've tried 50/50, just plain h20, it still runs the same.

5) The radiator cap has been replaced but it was several years ago, we've been fighting this for several years now on and off, and the different mechanics are either stumped by it or don't want to fix it so they make excusses i reckon. We have been to several places with the same results over and over, and are just tired of dumping money in it with no fix.

5) Bug's and litter, not sure about that one, i will check into that...

6) Not sure about the coolant flush kit but i will go take a look at it.

Thank you so much for taking time to help me out here Daniel.

Tyler

Boiling point of coolant > 212F
Bubbles/exhaust gases in radiator or auxiliary coolant tank when cold = bad Head Gasket.

Just using H20 is not enough for boil over protection of 212F.

Use Prestone extended life 50/50, and consider a new fan clutch from www.rockauto.com (http://www.rockauto.com).

The Prestone/Peak T flush kit can be bought at any local auto parts store near the Antifreeze section.

After purging the air out of the coolant system try running the HVAC on high heat max.
Are you getting Heat?

The blower from the HVAC system might keep her cool enough while waiting for a new fan clutch.

If there' s no coolant leaks, the other possible causes of over heat, and boil over. conditions are -
Blocked or contaminated radiator core
Blocked catalytic converter or exhaust system.
Engine running too lean, because of bad vacuum leaks or bad valves.

when you check for air bubbles in the coolant with the radiator cap off and the engine running you should see a solid flow of coolant coming out of the tubes.

The radiator must have no external corroded fins.

the timing if too retarded will cause high temps .

the radiator must be under 15 psi of pressure. if there is no pressure the the coolant will boil.

the fan clutch should not spin easy when cold. try to make it spin cold . if it goes around 2X then it is defective also if it has oil leak.

the plastic shroud must be in place. this causes air to be forced thru the radiator. no shroud the engine will run hot.

check the transmission is it low on fluid .

All good points to consider. Might I add removing the radiator cap only when the engine is stone cold and scraping the inside wall of the radiator with your fingernail. If you come up with a reddish/brown gunk on your finger that might be the true condition of your engines cooling system. It acts as an insulator effecting heat transfer and doesn't even show up in the free flowing coolant. If theres no or poor coolant flow in the radiator it may be the radiator core tubes are clogged. In this event you'll have to thoroughly flush the cooling system and have the radiator "rodded" out by a competent radiator shop or replaced along with the cap.
Other possibilities are an erroded water pump impeller or an erroded/broken reinforcement spring from the lower/return hose winding up in the water pump damaging the impeller and scattering throughout the system. These last two may not apply.
The cylinder head gasket is still a possibility. Luckily this is a simple truck to work on.

Hello all, we took it to the local radiator place and the man suggested that we try a new thermostat. We reluctantly changed it out and put in 50/50 with boil over protection and it's still overheating...


The clutch fan was turned cold, it has a litle resistance cold, when its warm it spins a little and then locks up. That should mean it's not the clutch right??


The old thermo was dirty brown like rust, it's not old at all, maybe a few months old.


Back to square one basically. The man at the radiator place said he could flush it for 60 bucks. I dont know what to think...

Hello all, we took it to the local radiator place and the man suggested that we try a new thermostat. We reluctantly changed it out and put in 50/50 with boil over protection and it's still overheating...


The clutch fan was turned cold, it has a litle resistance cold, when its warm it spins a little and then locks up. That should mean it's not the clutch right??


The old thermo was dirty brown like rust, it's not old at all, maybe a few months old.


Back to square one basically. The man at the radiator place said he could flush it for 60 bucks. I dont know what to think...

I guess you did not read my post #6 .

Fan clutch - Good
Thermostat - New
50/50 Coolant - Good
Radiator - Rust contamination
Plugged heat core ?
Plugged radiator core ?
Plugged catalytic convert, or exhaust system?

Is this truck getting heat from the HVAC high heat Max?

I guess you did not read my post #6 .


I did sir, but forgive me because i really have a very limited automotive background so some of the terms don't ring a bell with me. Terms like "no external corroded fins" and "retarded timing". The only thing retarded around here is me probably lol.

I did notice there is a chunk of shroud missing. Maybe 10-15% or so...

Is this truck getting heat from the HVAC high heat Max?

This jalopy had water leaking into the floor board from the heat so he had it removed/plugged or whatever. The AC is not working, it might blow air when he can get the dash to work. It's in bad shape no doubt about it guys. It has been doing a little better with the 50/50 and new thermo but its still bubbling after it gets hot.

corroded fins is what occurs when the radiator external cooling material is falling off. also if covered with debris you get the same effect of the engine overheating.

looking in to the radiator with the cap off to see the coolant flow with the engine running.

on the heater core . when this is disconnected these hoses must not be plugged up. you must connect the hoses together so that the flow is allowed back to the engine. this may be the reason its hot.

the engine must be properly timed . the distributor is adjusted to the correct timing spec. if the timing is retarded the engine is going to run hot. If the timing is too advanced the engine will make pinging sounds on acceleration.

the fan shoud is a common problem with older vehicles. plastic breaks. then the air is not sucked thru the radiator .

See AF ''OMG Coolant system corrosion w/pics''
http://www.automotiveforums.com/vbulletin/showthread.php?t=1083343

just do the head gasket. that's known issue on Silvies. instead of getting into pseudo scientific discussion.
you can buy "exhaust sniffer" and test your cooling system, if still in doubt

What size engine?
let me tell you my tale of overheating blues. changed every component that even so much as touched coolant, at least twice! Dealer was a complete waste of time because all he did was plug in his scan tool and said "yeah it's hot, but isn't throwing any trouble codes."
Was almost gonna junk it. BTW it's a '90 Suburban, 454, 2wd. A friend suggested an independant mechanic, so I figured I might as well drop another $100. He quickly determined that the bushings on the distributor shaft were totally shot. The bushings are like the "bearings" for the shaft. it turns out that the bad bushings was causing the timing to be very messed-up with some of the cylinders firing as much as 10 degrees off!!! this was forcing me to press on the pedal more, giving it more gas and heating up the engine more especially when I was pulling a trailer.

This is a relatively easy repair for a mechanic. A whole new distributor shaft assemlby is relatively inexpensive.