Bad week for my SC

Scott Long

Registered User
I was running errands the other day and ran into the credit union for about 5-10 minutes. When I came back out I noticed the windshield had a crack from left to right about 3-4 inches up from the bottom and runs clear across the entire window. The car was already warmed up and had been driven for about 20 minutes with the defrost blowing hot air on the windshield so I don't know why it would have cracked.

Stopped by a glass shop and got a quote for $185 installed for a new windshield. Cheaper than I thought but I didn't want to have to spend any money on the car right now.

Then the next night I was heading down to Indiana to go to a bar with my friend who lives there. I got about half way there and notice my temp gauge starts climbing up slowly higher than normal. This is odd, so I turn on my low speed fan. I have it on a relay w/ switch. The temp is in the low teens outside and I let the car warm up for about 15 minutes before I left. I've been driving for about 30 minutes. Anyhow its still getting hotter so I plan to stop at the next gas station (I'm in the middle of BFE on a 2 lane backroad/highway.) I notice if I get on the gas the temp guage goes down until I let off the gas and then it climbs up. Very odd.

Make it to the gas station and turn the car off, pop the hood, left the fan on. I tried to squeeze the upper radiator hose and it was hard as a rock. I have a pressure release radiator cap so I pop the safety valve and a lot of coolant goes into the resovoir. I slowly open the cap and it's still spraying all over the place so I pop it off and stand back. There is anti-freeze literally spraying out of my radiator about 3 feet up in the air and its all over the motor/ic/battery/fenders.... I'm pretty ticked off at this point.

I let it sit about 20 minutes and go buy a gallon of 50/50 from inside the gas station and fill the radiator up it took almost the entire gallon. I put the cap back on and start the car up. This time the temp gauge is back down on C and I let it run about 10 minutes and it is sitting nice and normal. I decide I'm going to take it home and not chance going out of state with it possibly having issues.

I make it home about 30 minutes later, fan off the entire trip, heater is warm, and the temp never got above normal range where it always sits.

Very strange.

My windshield is fogged up though. I figure it popped a leak in the heater core since you can smell antifreeze in the car.

The next morning I check it and its full of anti-freeze so I start it up and drive to auto zone and get a new radiator cap just to be safe. Then I remember the smell so I grab a bottle of bars liquid aluminum. I pop the hood while its running and there is steam coming from the radiator down behind the fan (radiator is 1 yr. old) so I take it home and let it cool down and then add the stop leak and let it run for about 30 minutes while I shovel out the drive and walk way. I pull it out of the garage and drive it around a bit, temp is fine steam in windshield goes away.

For the past few days it's been fine, I check the radiator each morning and it's full. However the temp guage still goes down to the bottom every time I accelerate above 1/4 throttle, then it bounces back up. This has me worried. Is the sender bad, or maybe an air pocket trapped in it? My vent is stuck shut, I tried to remove it but it started to twist the entire pipe so I left it alone. I could pull the t-stat housing and put it in a bench vise and open the vent but it's not leaking and the t-stat is like a year old so I don't want to mess with it.

I also wonder what would have caused the car to get so damn hot. I tested the anti-freeze a few weeks ago and it was good to -34 so I doubt I got ice in the block. It's not leaking steam anymore since I put the stop leak in it. So hopefully it's all good now. I don't want to pull the dash for a heater core job and I really don't want to buy another radiator.

I'm stumped as to why it overheated. If the radiator or heater core was leaking it wouldn't pressurize the cooling system but it had so much pressure I thought the upper hose was going to burst at the gas station.
 
i think u may have solved the pressure problem with the new rad. cap.

my 94 altima does the thing with the coolant. when its about 1/2 way to normal operating temp. i'll take it to about 4-4.5k and the needle will go immidiately back to C. then it takes a few mins to get back to normal. i never thought anything was wrong with my system. i've got a new radiator, water pump and cap.

i just figured the water pump was circulating so fast.
 
Well the cap wasn't that old but I changed it regardless, maybe it failed. Not like it can't happen right?

I do have ASP underdrives on the car, but have had them for over 6 mo's and never had any problems with cooling. I wonder if the water pump is getting weak? It's about 80k miles old. Its not dripping out of the hole and there is no play front to back with it.

I just don't know why it would have got so much pressure and overheated. Maybe the cap was just bad. I got a new pressure release cap, it's made by CST (Cooling System Technologies). I believe its rated to 16 lbs.
 
First off, is the guage actually dropping all the way to cold above 1/4 throttle, or just cooling down in the normal range? If it cools below the norm range, then yes there is definately a problem with the temp sender or guage. Test the sender first. If you need the test procedure and res values pm me and I can send them to you.

As for the rest, definately do whatever you need to get the air bleed valve open. If you added a gal without it open, it is quite possible there are air bubbles in the stream.

If the pressure was really going that high there could be blocks in the coolant passages interferring with flow. This could possibly explain why coolant isn't circulating properly at low rpm, but starts to get sufficient flow when you accellerate, although doesn't seem very likely, especially if you are getting normal and consistant heat output from the heater core.

One other highly unlikely prob as you say you definately had a coolant leak is bad oxygen sensors. When the sensors go on the 3.8, it tends towards a very lean fuel mixture, significatly increasing cylinder temps. When you apply throttle, it will be enriching the mixture towrds rich for acceleration, so even if it isn't enriching as much as it should be, it is enriching enough to not be on the excessively lean end and therefore allowing the cylinders to cool down somewhat. Try popping out a couple of the easier to reach spark plugs and check them. If its running overly lean, the plugs will give you a sign. I've seen some fords with bad o2's running lean actually heat the spark plug so bad it started melting the electrode and it was hanging down like a hook. Check the gap. If you haven't changed your 0xygen sensors in the last 45,000 miles, you should be swapping them as part of standard maintenance regardless.
 
Sounds like you have a water pump that is losing its abilty to get the job done at low RPM's. I had this problem on my car also, and waited to long to fix it and now I get to do head gaskets.

My vent pipe started to twist the last time I burped my cooling system.
I got a pair of vice gripe pliers on the pipe, while I removed the threaded plug

I also found out that their are a lot of junk caps around, I have made a point to stick with name brand cooling components.

Have you ever heard of using black pepper or a raw egg to seal a cooling leak. It's a click and clack special treatment!
 
Never heard of that egg and pepper?

I know it could use new 02's but the car runs rich. I have soot on the bottom of the tail pipe cutouts on the bumper.

The water pump I know works fine because it's not overheating. If I get on the gas, the gauge goes all the way down to the edge of cold where it's completely bottomed out and stays there till I let off the gas pedal and then it goes up quickly to where it should normally read.
 
Never heard of that egg and pepper?

I know it could use new 02's but the car runs rich. I have soot on the bottom of the tail pipe cutouts on the bumper.

The water pump I know works fine because it's not overheating. If I get on the gas, the gauge goes all the way down to the edge of cold where it's completely bottomed out and stays there till I let off the gas pedal and then it goes up quickly to where it should normally read.

Then you probably just have a problem with the sender/guage. If it drops when you get on the pedal, more likely a prob with the guage rather then the sender. There's no way it can suddenly cool itself below operating temp whenever it gets loaded.

Best solution for the problem is to sell the SC and buy something reliable like a honda :eek:

Joking! Don't tar and feather me! :p
 
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I have been thinking about trading my SC for an ugly dog, then shoot the dog!

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never mind I feel better now, I just torqued my heads
 
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I just don't know why it would have got so much pressure and overheated. Maybe the cap was just bad. I got a new pressure release cap, it's made by CST (Cooling System Technologies). I believe its rated to 16 lbs.

You seem pretty knowledgeable, but i figure i would point this out. The pressure might only be at 16 lbs in the cooling system etc. 16lbs of pressure is more than twice atmospheric. I'm not going to pull out my "Thermals and fluid dynamics" book to get the exact amount, but that raises the boiling point of you coolant. So you heat the coolant up and it's not boiling. Now you remove the extra pressure and return it to atmospheric. The ALL the coolant begins to boil all at once, and the only place for it to go and it literally ERUPTS out of the radiator. This is why they tell you not to remove the radiator cap when the motor is hot.
 
Ok I didn't know that it kept the boiling point higher when it's under pressure. I wonder if my old cap was bad or somehow it didn't vent under overpressure. The upper hose was so tight it felt like it was going to burst. Usually its tight but you can squeeze it a bit, that night it felt solid.

If the cap was bad, wouldn't it have overheated on my way back home of 35 minutes? I changed it the next morning but I had drove it around for a while first and it never got hot again. That's what has me stumped.

I think I'll get a new sending unit for the t-stat housing since that is the cheapest part for the SC ($3.99) and when I have it out I'll bleed the air in the system through that hole.

I've already broken one t-stat housing trying to get a stuck vent open. It's not so easy to find a new one. Definately not a same day thing. If it was an SBC or SBF I could just go to the local parts store and get a new one from the chrome section.
 
I think I'll get a new sending unit for the t-stat housing since that is the cheapest part for the SC ($3.99) and when I have it out I'll bleed the air in the system through that hole.

I don't see how you can bleed the cooling system from the sensor hole since it isn't the highest point.

I've already broken one t-stat housing trying to get a stuck vent open. It's not so easy to find a new one. Definately not a same day thing. If it was an SBC or SBF I could just go to the local parts store and get a new one from the chrome section.

It's a good idea to hold the vent neck with an open wrench while loosening the vent bolt.
 
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