GAslim78

ok,

So I've got this olds 98 (403 big block) ... one day the heatercore went bad and smoke poured into the cab. He straight hooked the hoses for it and rode like that for about a week.then it overheated on the highway one day about 2 months ago. Unfortunely the temp light wasnt working at the the time so I didnt realize it was overheating until it cut off. I replaced the thermostat and water pump first, and it still overheated. I found a small hole in the radiator and replaced it, and it still overheated. Then I found someone online telling me that the missing heater core is the problem, and that old big engines displace heat this way. I replaced that and it still overheated, but it toot alot longer ... so much so that the car seemed fine for about two days. I then found that the oil pressure switch was worn and leaking oil, replaced it and it seemed to be fine until today. we also have found a leak from the Exhaust flange from manifold to pipe. I have been riding it easy, but then i was shopping around town today and it started acting up. First while i was accelerating it fluttered like it didn't want to go and a heard a 'pop' (only way I can describe it) and it picked up and was fine. If I push to hard on the pedal it makes a fluttering sound like it would when the car was overheated badly and wouldnt accelerate - but I get acceleration.

Then I stopped at a place for about 15 miniutes and when I got in and started her up the temp light was on, and it kinda smelled like it had been running hot. she rode fine other than the fluttering noise, but the radiator was a LITTLE hot when I got him.

my mech. thinks that I may have burnt a valve or two overheating the car so badly, and so often. Anyone have any other ideas?

ALSO

before the heatercore when bad I had heat obviously, but the blower motor was bad so it just ceeped out .... I replaced the motor and heartercore and now for some reason the heat wont work. My mech things it might be the selector.

70 cutlass s

Lets start with a 403 is a small block. How many times have you overheated it. I would have said blown head gasket, or even a cracked head, but driving it hot a lot. I would say that the engine is ruined.

I think the reason why your heat isn't working is because of a cracked block, or head.

jeffreyalman

bypassing the heater core will not cause any problems unless the lines are hooked up wrong or blocked off, nor will (should) a bad heater core cause overheating, on it's own, but if all the coolant leaked out INTO THE PASSENGER FLOOR you would have known it, it would have taken weeks and you'd have had fogged windows, so chances are it happened under way as you described, however:

if you drove it hot and kept going, none of that matters, it's fried.

sad, but may be salvageable if enough $$$ thrown at it... head gasket and head machined, etc.

But you must find the cause of the overheating.

GAslim78

Well, ive got NO water in the oil, NO white smoke, and no visible or novisible signs of a head problem .. well .. other than it overheating It's overheated probably 6 or 7 times, 2 times so bad that it would not run until it cooled off.

I could also have the wrong thermostat in it, like its not opening soon enough.

GAslim78

also, I could walk outside right now and drive the car all over town ... it doesnt 'run hot' now.

Olds64

Do a compression test.

J-(Chicago)

If you can drive around town just fine and cool,
but it gets really hot under higher rpm loads, the radiator is probably way too small, or clogged.

Always put your thermostats in a pot of water and boil them before install, to make sure they open correctly and at the right interval.

GAslim78

Ok, me and my mech. will do a compression test and get the results back if it does/does not solve the problem. My mech also said this mourning that he thinks the radiator might be too small ... which is a pain cos now I will have to buy a more expensive one when I just spent 120 on that one.

thanks for the help, Ill get back to you.

GAslim78

My mech. is supposed to come by this afternoon and do a compression test ... but im preparing for the worst ... what would you guys rec. -- rebuild the head of replace the head? I can get a pair of used trans 403 heads for 150 bucks ... suggestions?

J-(Chicago)

120 for a radiator is a steal. It's probably way too small at that price.

I have a Brass tank 4 row truck radiator in mine, and I got it for a steal at $250 as a blemish.

Olds64

Sounds like you might want to get another mechanic. If he thinks the radiator he put on the car is too small then he is a moron. If you put a radiator on a car and it is a stock radiator then it is just fine. If he put an aftermarket radiator on it then it wouldn't have cost $120, even for a small one. Chances are you're radiator is the correct size if he bought the repalcement from a reputable auto parts store. I suggest doing the compression test and having your radiator pressure tested, just to make sure the new one isn't leaking.

GAslim78

hey, if your going to insult the people I work with, please do not respond to this post. I dont need MORONS calling people MORONS. good lord. I purchased the radiator myself, he just put it in, so if anyone did something wrong its me ... I came here for help, not insults.

Texas Jim

GASlim78,
Did you read the plugs? I rarely hear anyone say that they read the plugs and it told them... Reading the plugs, ie; in a situation like yours, will send you in the correct direction as to the problem, if indeed a problem exists. If you do have a bad head gasket and/or a bad head, the vacuum gauge will tell you what's going on. Yes, a compression test is great, but reading the plugs and using the vacuum gauge will tell you alot more. Check the vital signs first, and go from there. Best of luck w/ the engine, sincerely.

Olds64

Sorry. I was just suspicious of your mechanic. It is difficult to troubleshoot a problem on-line. We are here to help. I didn't mean to offend.

Lady72nRob71

If the car ran okay with the original radiator before, then it was NOT too small. They do not shrink, but they could get plugged up. How does it look after draining it? It should be a 3 core. Our top thermostat choice is a 180*. verify its operation in some water on the stove before installing.
You say it has been running strange - if running lean, or out of time, that could cause overheating. Check mixture and timing. Vacuum leaks and failled emission controls can cause lean mixtures or affect timing advance.

If it overheats between stoplights and okay on the highway, the thermal fan clutch might be shot.
When it is running very hot, pop the hood with the engine running, stand at the feft fender, poke your head just under the hood. You should hear the roar of the fan moving lots of air and your hair should be blowing all over. If not, it may be just freewheeling when it should be engaged. My car had this issue - a new clutch fixed it.

A cheap ($10) infrared thermometer makes checking car temps very easy.

We often see inexperienced mechanics replacing parts at will to try to fix a problem(rather than proper diagnosing) and running up huge bills for their customers. Sometimes we bite at them as we do not like seeing people overcharged for things they do not need.
Case in point - my neighbor had similar issues with his old taurus. It overheated in hot summer and always with A/C on. He took to the dealer and local places for over a year. They changed radiator, hoses, t-stat, even replaced the head gaskets. Fan turned, so it was deemed ok. Even the dealer did not diagnose - just replaced stuff.
Finally some smoke came out from under the hood and I went to check it out for him. The low speed of the radiator fan worked but the high speed did not. The fan bearings did not allow the fan to come up to high speed. Bearings finally wore bad enough that the high speed winding finally overheated, shorted and burned up the wiring. I replaced the fan for him and he never had a problem again.
His cost for unneeded work - 800+
Fan module - 125 online
Cost for me to install fan - a few beers and dinner
My satisfaction - priceless...

greenslade

After extensive trouble shooting .... replaced fuse!lol

GAslim78

If the car ran okay with the original radiator before, then it was NOT too small. They do not shrink, but they could get plugged up. How does it look after draining it? It should be a 3 core. Our top thermostat choice is a 180*. verify its operation in some water on the stove before installing.
You say it has been running strange - if running lean, or out of time, that could cause overheating. Check mixture and timing. Vacuum leaks and failled emission controls can cause lean mixtures or affect timing advance.

OK, Ill respond best I can .... I DONT have a 3 core radiator, which has been identified as atleast ONE of the problems. the 'stock' one from my local autozone - matched to my car - is a 1 core. So I do know that if anything, this radiator is NOT going to be good enough. We did all those termo. test and the termo. was fine.

As far as the vacuum/lean part .... Im sure that my vaccum lines need to be reran ... I do know that a few are broke/missing, and we JUST FOUND OUT that a clear line going from the vapor storage canister is broken, and from what we can tell via diagrams online and the car is is either the line to the vacuum signal or the bowl vent. obviously we need to replace it.

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If it overheats between stoplights and okay on the highway, the thermal fan clutch might be shot.
When it is running very hot, pop the hood with the engine running, stand at the feft fender, poke your head just under the hood. You should hear the roar of the fan moving lots of air and your hair should be blowing all over. If not, it may be just freewheeling when it should be engaged. My car had this issue - a new clutch fixed it.
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Well, it runs good a low speeds/rpms ... if you run too long, too hard, too fast it runs hot. And the cooliant isnt hot, its the oil ..... which says head, but like I said before their are NO outward signs of a head problem .. no oil, no water in oil, no nothing. Im not losing coolant unless I open the radiator. *shrug* I dunno. I drove it yesterday *for about 5 minutes* and it ran GREAT - minus the carb, which needs rebuilding - and didnt run hot while i was riding.

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A cheap ($10) infrared thermometer makes checking car temps very easy.

We often see inexperienced mechanics replacing parts at will to try to fix a problem(rather than proper diagnosing) and running up huge bills for their customers. Sometimes we bite at them as we do not like seeing people overcharged for things they do not need.
Case in point - my neighbor had similar issues with his old taurus. It overheated in hot summer and always with A/C on. He took to the dealer and local places for over a year. They changed radiator, hoses, t-stat, even replaced the head gaskets. Fan turned, so it was deemed ok. Even the dealer did not diagnose - just replaced stuff.
Finally some smoke came out from under the hood and I went to check it out for him. The low speed of the radiator fan worked but the high speed did not. The fan bearings did not allow the fan to come up to high speed. Bearings finally wore bad enough that the high speed winding finally overheated, shorted and burned up the wiring. I replaced the fan for him and he never had a problem again.
His cost for unneeded work - 800+
Fan module - 125 online
Cost for me to install fan - a few beers and dinner
My satisfaction - priceless...
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well, just to put some people at ease this guy is my best friend, and I havent paid a dime or labor for anything he's done to the car ... and everything I've purchased/replaced needed to be replaced anyway, as it was original, so I guess it aint so bad.

I just want her to run good.

GAslim78

also, we did a compression test and everything was fine. *shrug*. BUT when we got to the last spark plug (very back on on left side of engine if you are looking at engine) was covered in oily junk when we pulled it, and we were SURE we had found the problem ... we even had to clean the compression tester off after trying to screw it in ... but comp was fine there too.

Lady72nRob71

I might have caused some confusion earlier.
When I say 3 core radiator, it means three rows of tubes going side to side. You have to look inside the filler neck to see them. I never heard of a 1 core in a car like yours, but 2 cores are out there. Three is minimum with A/C or large engine. Four is better.
Does the car have the rubber baffels surrounding the front radiator area? They funnel air from the grille through the rad - needed on the highway...

So you say the oil is running hotter than the oil? Never heard of that complaint, but it sounds logical since the oil is in diect contact with all those hot parts.
If this is really the case, then a GOOD flush of the block coolant passages is needed, as some areas of the motor could be blocked or clogged with sediment. The drain plugs on the block will need to be pulled and flushed with a high pressure garden hose.

Do work on the vacuum lines. Running lean can get it hot when out on the highway also. The oil on one plug could mean a leaking valve guide seal if the compression is okay. It would normally not cause overheating.

Hope this helps some more...

GAslim78

Sorry it took me so long to respond again, but life took over and I havent messed with the car since. but Ive found some itme

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I might have caused some confusion earlier.
When I say 3 core radiator, it means three rows of tubes going side to side. You have to look inside the filler neck to see them. I never heard of a 1 core in a car like yours, but 2 cores are out there. Three is minimum with A/C or large engine. Four is better.
Does the car have the rubber baffels surrounding the front radiator area? They funnel air from the grille through the rad - needed on the highway...

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well, the same parts store gives me a STOCK 1972 starter for my 1970 mavrick, so its not hard for me to believe that this is the wrong radiator.

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So you say the oil is running hotter than the oil? Never heard of that complaint, but it sounds logical since the oil is in diect contact with all those hot parts.
If this is really the case, then a GOOD flush of the block coolant passages is needed, as some areas of the motor could be blocked or clogged with sediment. The drain plugs on the block will need to be pulled and flushed with a high pressure garden hose.

Do work on the vacuum lines. Running lean can get it hot when out on the highway also. The oil on one plug could mean a leaking valve guide seal if the compression is okay. It would normally not cause overheating.

Hope this helps some more...

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that sounds like a good thing to do regardles if it fixes the problem or not ... but ... could running out of time cause this overheating prpblem?

we cranked her up this mourning and she ran [pretty good, we didnt drive, but sat in the drive for about 20 min. she didnt run hot, but was getting hot. we we cranked her again later, she all the sudden sounded very choppy, and out of time ... maybe my timing chain is slipping, and needs to be replaced?