99 STS Overheating and no heat

[BodybyFisher]

Are you using straight water?

[Ranger]

Does using dexcool/water instead of straight water raise the boiling point?

It's the pressure that raises the boiling point. Coolant under 16 psi raises it to about 265. NEVER use straight coolant or straight water. Sounds like you still have "air" in the system. When you refill the system, you need to rev it to 3k - 4k a few times to purge the air. THEN cap it up and take it for a ride and get the R's up a few more times. Come back, let it cool down and check the level again.

[mcampau]

Are you using straight water?

For right now with testing purposes, yes. I didnt want to literally throw money away with buying dexcool.

[mcampau]

Does using dexcool/water instead of straight water raise the boiling point?

It's the pressure that raises the boiling point. Coolant under 16 psi raises it to about 265. NEVER use straight coolant. That will actually lower it. Sounds like you still have "air" in the system. When you refill the system, you need to rev it to 3k - 4k a few times to purge the air. THEN cap it up and take it for a ride and get the R's up a few more times. Come back, let it cool down and check the level again.

I did that when filling it with water.

[BodybyFisher]

At 15 psi, water boils at 248 degrees,

Coolant boils at 265 degrees at 15 psi

The problem is that we do not know if your cooling system is holding pressure, if its not holding 15 psi, it will boil lower

PRESSURE TEST THE SYSTEM

and

NEVER USE STRAIGHT WATER, you will have a lot of trouble balancing the cooling system now, to 50/50

[mcampau]

At 15 psi, water boils at 248 degrees,

Coolant boils at 265 degrees at 15 psi

The problem is that we do not know if your cooling system is holding pressure, if its not holding 15 psi, it will boil lower

PRESSURE TEST THE SYSTEM

and

NEVER USE STRAIGHT WATER, you will have a lot of trouble balancing the cooling system now, to 50/50

Ill hunt around tomorrow to try and find the correct adaptor to pressure test it.

There were a lot of chunks of what I have to guess to be some sort of stop leak in the reservoir. I wonder if there are more chunks in the rest of the system causing these problems??

[JimD]

Thanks Jim, I didnt know that the electric parking brake release was in 99, it is my understanding that the programmer has a vacuum connection is that not true in 99?

Major changes took place when the Seville was put on the K Platform in 1998.

[BodybyFisher]

At 15 psi, water boils at 248 degrees,

Coolant boils at 265 degrees at 15 psi

The problem is that we do not know if your cooling system is holding pressure, if its not holding 15 psi, it will boil lower

PRESSURE TEST THE SYSTEM

and

NEVER USE STRAIGHT WATER, you will have a lot of trouble balancing the cooling system now, to 50/50

Ill hunt around tomorrow to try and find the correct adaptor to pressure test it.

There were a lot of chunks of what I have to guess to be some sort of stop leak in the reservoir. I wonder if there are more chunks in the rest of the system causing these problems??

Keep checking the purge line to make sure that its flowing and clear, if you are finding stuff, it can make itself to the 'bolt with a hole' in it and clog it.. If I were you, I would pull the 'bolt with a hole' in it and check that it is fully clear

Your heater is working odd, maybe stop leak has clogged it, you may need to flush the heater core

Its possible that someone thought that it had bad head gaskets and put some sort of sealer in there. By the way sealers do not work for NS head gaskets

[BodybyFisher]

Go to this link, and see the EFFECT OF SYSTEM PRESSURE ON BOILING POINT chart

http://www.avenger-valkyrie.org/techinfo/antifreeze.htm

[Ranger]

There were a lot of chunks of what I have to guess to be some sort of stop leak in the reservoir. I wonder if there are more chunks in the rest of the system causing these problems??

Check to see if they clogged the purge line and then I'd flush the radiator and heater core.

[mcampau]

I flushed the system for quite a while and got a lot of small chunks of that stop leak crap. Im trying to find the proper adaptor for the cooling system pressure tester. The only one I can find is at Napa and its $90! Im sorry but that is freaking ridiculous.

Is there a heater core in the rear of this car?? When I bought the car the rear passenger side floor was soaking wet. I vacuumed it up and used a deep cleaner to suck the rest of the water out. That was 4 days ago. It's been sitting in my garage with the windows down to dry up the rest of the way but now there's even more water!

[mcampau]

I pressure tested the cooling system. After pumping it to about 17 psi I left it alone for 30 minutes and it was between 16 and 16.5 psi. Then I released the pressure and ran the engine. It took awhile for it to build pressure, but it did steadily. after about 10 minutes it finally reached 16psi. The needle was rock solid with no bouncing (like I would expect with a head gasket). However when I reved up the motor the pressure would drop slightly then snap up to a pressure slightly higher than it was to begin with.

I tested the cap (brand new) and it wouldn't hold pressure worth a crap! It dropped from 16 psi to 0 in about 4 or 5 seconds.

[BodybyFisher]

Not sure why you are increasing pressure when you rev the engine, that does not sound good

That cap must go, but an OEM cap

If she still overheats with a new cap, I would test the coolant for combustion by products, buy the kit from NAPA

[BodybyFisher]

I flushed the system for quite a while and got a lot of small chunks of that stop leak crap. Im trying to find the proper adaptor for the cooling system pressure tester. The only one I can find is at Napa and its $90! Im sorry but that is freaking ridiculous.

Is there a heater core in the rear of this car?? When I bought the car the rear passenger side floor was soaking wet. I vacuumed it up and used a deep cleaner to suck the rest of the water out. That was 4 days ago. It's been sitting in my garage with the windows down to dry up the rest of the way but now there's even more water!

Water in the rear passenger area usually is related to the sunroof, you have a sunroof?

If the heater core was leaking you would get water by the front passenger foot area, but your system held pressure pretty good, it sounds like a sunroof leak

[mcampau]

Not sure why you are increasing pressure when you rev the engine, that does not sound good

That cap must go, but an OEM cap

If she still overheats with a new cap, I would test the coolant for combustion by products, buy the kit from NAPA

I bought the block test kit from Napa and the fluid went from blue to translucent green. Unfortunately I think that's close enough to yellow to call it a bad head gasket. CRAP! Now the real fun begins.

[mcampau]

I flushed the system for quite a while and got a lot of small chunks of that stop leak crap. Im trying to find the proper adaptor for the cooling system pressure tester. The only one I can find is at Napa and its $90! Im sorry but that is freaking ridiculous.

Is there a heater core in the rear of this car?? When I bought the car the rear passenger side floor was soaking wet. I vacuumed it up and used a deep cleaner to suck the rest of the water out. That was 4 days ago. It's been sitting in my garage with the windows down to dry up the rest of the way but now there's even more water!

Water in the rear passenger area usually is related to the sunroof, you have a sunroof?

If the heater core was leaking you would get water by the front passenger foot area, but your system held pressure pretty good, it sounds like a sunroof leak

I think you are right on the sunroof leak. Ill have to pull some panels and find the drain hoses.

[BodybyFisher]

Do a search here, we have had a lot of members with the sunroof leak, there is a lot of info,

[Ranger]

I bought the block test kit from Napa and the fluid went from blue to translucent green. Unfortunately I think that's close enough to yellow to call it a bad head gasket. CRAP! Now the real fun begins.

Not sure if you did or not, but you should not run the test soon after adding coolant. Doesn't sound good though.

[mcampau]

It's water that's in it right now. I flushed the system 2 days ago and didnt want to waste $30 worth of coolant.

[caddypete]

Did you take the bolt with the hole out like Ranger suggested AND CHECK TO SEE IF IT WAS NOT PLUGGED? I have not drove my Caddy anywhere far for months because of it losing coolant on any drive over 20 miles and once it lost its coolant, it would lose 2 gallons in 5 miles. It has a new radiator and could idle all day and never move off the 1/2 mark of the temp gauge. Would hold pressure under a pressure test all night long without losing a pound.Never could find a leak but lost coolant so quick when driven. Pulled that hollow bolt that comes out of the water pump and goes to the reservoir and found it 90% restricted. It causes the pressure to build up in the reservior tank and the cap releases all the coolant down the over flow hose when taken in the higher rpms.It also tested bad for exhaust in the coolant, then after retesting with the coolant that was in there for the short trips that I would take it on it passed the test. Was pretty sure it wasn't losing all that coolant out the exhaust I'm sure I would have noticed the cloud behind me and don't think the engine would have run to well with that much coolant dumping into it.