Why is the Coolant in reservoir boiling over.

LOCASH · 07-30-2002, 08:48 AM

It happened when I went to the auto-x also.

Today I actually opened the hood and noticed that the coolant in the res. was boiling over.

I have a Black Magic but have never had a problem with it before. The wierd part is that the guage inside was about on the "R" in NORMAL when it happened. Any ideas?

Jeff Chambers · 07-30-2002, 11:37 AM

I would suspect a blown head gasket. The most common reason for pushing excess amounts of water (more than normal thermal expansion) into the resevoir is cylinder pressure driving it there. This usually means head gasket problems. Since your temperature doesn't seem to be excessive, it'd also seem to say that cylinder pressure is pushing the water out.

jerrys84 · 07-30-2002, 11:46 AM

what he said

Chevyguy · 07-30-2002, 01:00 PM

If no oil shows up in the coolant, then a cracked head/exhaust port etc allowing exhaust or combustion pressure directly into the coolant.

My POS Cavalier did this, I changed the head gasket and it was fine and the head was very straight, But lots of green dried stuff on one piston, then started loosing coolant. Eventually the cat converter plugged up with coolant residue.

Jeff Chambers · 07-30-2002, 02:24 PM

Good point. Not quite as common, but definitely another way for the coolant side to get pressurized.

LOCASH · 07-30-2002, 02:33 PM

If the head gasket is blown, will it push the coolant out all of the time (when the T-stat is open)? It only seems to happen after I drive it for a while.

silver_pilate · 07-30-2002, 02:47 PM

Possibly a simpler explanation.?.

Couldn't he just be boiling his coolant. I know my car has done this periodically in the past when I was dealing with overheating issues secondary to underdrive pullies on my modded motor. Of course, my temp gauge read higher than LOCASH's, but then again, the factory temp gauge isn't all that accurate.

Occam's Razor: one should not increase, beyond what is necessary, the number of entities required to explain anything.

Just a thought.

--nathan

jerrys84 · 07-30-2002, 03:41 PM

just thought of this, try a new cap...

had a similar situation once, and it ended up being a weak cap.

maybe not, but it's worth a try...

magicmerll · 07-30-2002, 04:21 PM

I was really hoping someone was going to mention that!

Try a radiator cap.

The cap is designed to hold pressure in the radiator. The more pressure water is under, the higher it's boiling point. If your cap is week, your boiling point is low, possibly as low as 212 degrees, the normal boiling point for water. It is not uncommon for an engine to run this temp., therefore the pressure cap is necessary.

Your water is simply boiling because it's hot, not because of some supercalafragalistic cylinder pressure. Who ever heard of 5.0 blowing a head gasket anyway? Come on guys...

LOCASH · 07-30-2002, 04:23 PM

I am not being at all sarcastic-could someone explain how a bad rad cap would cause my res. to fill with boiling coolant? I think it may happen when I really get on the engine. It happened once at the auto-x and it happened again today when I was trying to get away from the Italian Police. I saw them parked on the side of the road and it was really obvious that I was speeding. As soon as they pulled out I floored it for about 2-3 mins. to make it home. I drove the car to work and back (about 15 mins. one way) earlier the same day with no problems though. I'm sure you guys know more about this than me, but does it still sound like a head gasket? Thanks alot for all of your help. I really appreciate it.

LOCASH · 07-30-2002, 04:29 PM

Quote:

I was really hoping someone was going to mention that!

I was too! I was writing while you were replying. I have one on the way but I will try the Auto store on base. I really hope its just the cap. (Who wouldn't?) Thanks for the explanation also.

LOCASH · 08-01-2002, 03:04 PM

I replaced the cap and it hasn't happened since. Thanks to all of you for taking the time to help a stranded Stanger. I really appreciate it.

07-30-2002, 08:48 AM	#1
LOCASH Registered Member Join Date: Oct 2000 Location: Santa Lucia di Budoia, Italy Posts: 217	Why is the Coolant in reservoir boiling over. It happened when I went to the auto-x also. Today I actually opened the hood and noticed that the coolant in the res. was boiling over. I have a Black Magic but have never had a problem with it before. The wierd part is that the guage inside was about on the "R" in NORMAL when it happened. Any ideas? __________________ 86 GT T-tops

07-30-2002, 11:37 AM	#2
Jeff Chambers Moderator Join Date: Aug 2000 Location: Milan, OH Posts: 2,699	I would suspect a blown head gasket. The most common reason for pushing excess amounts of water (more than normal thermal expansion) into the resevoir is cylinder pressure driving it there. This usually means head gasket problems. Since your temperature doesn't seem to be excessive, it'd also seem to say that cylinder pressure is pushing the water out. __________________ Jeff Chambers 1990 Mustang GT 10.032 Seconds / 137.5 MPH 14-time Street Warrior World Record Setter CRT Performance 2001 Tropic Green Mustang GT - 12.181 / 113.2 MPH 2002 Ford F-250 Crew Cab 7.3l Power Stroke - 17.41@77.2 "There's nothing boring about a small block automatic shifting gears at 9400 rpm!"

07-30-2002, 11:46 AM	#3
jerrys84 Registered Member Join Date: Feb 2002 Location: minnesota Posts: 129	what he said __________________ 91 LX 'work in progress' previous stangs; lightly modded 84GT 81 2.3 converted to 302 auto

07-30-2002, 01:00 PM	#4
Chevyguy Backyard Mechanic/Chemist Join Date: Feb 2001 Location: Acton MA USA Posts: 435	If no oil shows up in the coolant, then a cracked head/exhaust port etc allowing exhaust or combustion pressure directly into the coolant. My POS Cavalier did this, I changed the head gasket and it was fine and the head was very straight, But lots of green dried stuff on one piston, then started loosing coolant. Eventually the cat converter plugged up with coolant residue. __________________ 2001 Crown Vic Maurader Airbox/MAF, DR chip Edel IAS shocks Single exhaust :wtf: 93 P-71 Vic interceptor Backup car now 90 5.0 LX Notch SOLD 74 Chevy Laguna type S-3 454 under construction Currently apart undergoing bodywork.

07-30-2002, 02:24 PM	#5
Jeff Chambers Moderator Join Date: Aug 2000 Location: Milan, OH Posts: 2,699	Good point. Not quite as common, but definitely another way for the coolant side to get pressurized. __________________ Jeff Chambers 1990 Mustang GT 10.032 Seconds / 137.5 MPH 14-time Street Warrior World Record Setter CRT Performance 2001 Tropic Green Mustang GT - 12.181 / 113.2 MPH 2002 Ford F-250 Crew Cab 7.3l Power Stroke - 17.41@77.2 "There's nothing boring about a small block automatic shifting gears at 9400 rpm!"

07-30-2002, 02:33 PM	#6
LOCASH Registered Member Join Date: Oct 2000 Location: Santa Lucia di Budoia, Italy Posts: 217	If the head gasket is blown, will it push the coolant out all of the time (when the T-stat is open)? It only seems to happen after I drive it for a while. __________________ 86 GT T-tops

07-30-2002, 02:47 PM	#7
silver_pilate DURKA DURKA!! Join Date: Sep 1997 Location: Lubbock, TX...(TX panhandle) Posts: 1,418	Possibly a simpler explanation.?. Couldn't he just be boiling his coolant. I know my car has done this periodically in the past when I was dealing with overheating issues secondary to underdrive pullies on my modded motor. Of course, my temp gauge read higher than LOCASH's, but then again, the factory temp gauge isn't all that accurate. Occam's Razor: one should not increase, beyond what is necessary, the number of entities required to explain anything. Just a thought. --nathan __________________ '91 GT, Coast 347, 9.5:1 compression, full intake, Wolverine 1087 cam, exhaust, Keith Craft ported Windsor Jr. Irons (235 cfm intake, 195 cfm exhaust), AOD, PI 3500 converter, Lentech valve body, 3.73's (4.10's in the works), and Yokohama ES100's out back. Daily Car: '04 Infiniti G35 Sedan 6MT

07-30-2002, 03:41 PM	#8
jerrys84 Registered Member Join Date: Feb 2002 Location: minnesota Posts: 129	just thought of this, try a new cap... had a similar situation once, and it ended up being a weak cap. maybe not, but it's worth a try... __________________ 91 LX 'work in progress' previous stangs; lightly modded 84GT 81 2.3 converted to 302 auto

07-30-2002, 04:21 PM	#9
magicmerll Registered Member Join Date: May 2002 Location: St. Louis, MO Posts: 19	I was really hoping someone was going to mention that! Try a radiator cap. The cap is designed to hold pressure in the radiator. The more pressure water is under, the higher it's boiling point. If your cap is week, your boiling point is low, possibly as low as 212 degrees, the normal boiling point for water. It is not uncommon for an engine to run this temp., therefore the pressure cap is necessary. Your water is simply boiling because it's hot, not because of some supercalafragalistic cylinder pressure. Who ever heard of 5.0 blowing a head gasket anyway? Come on guys... __________________ Ever notice the people that know the best way to raise kids are the people that don't have any?

07-30-2002, 04:23 PM	#10
LOCASH Registered Member Join Date: Oct 2000 Location: Santa Lucia di Budoia, Italy Posts: 217	I am not being at all sarcastic-could someone explain how a bad rad cap would cause my res. to fill with boiling coolant? I think it may happen when I really get on the engine. It happened once at the auto-x and it happened again today when I was trying to get away from the Italian Police. I saw them parked on the side of the road and it was really obvious that I was speeding. As soon as they pulled out I floored it for about 2-3 mins. to make it home. I drove the car to work and back (about 15 mins. one way) earlier the same day with no problems though. I'm sure you guys know more about this than me, but does it still sound like a head gasket? Thanks alot for all of your help. I really appreciate it. __________________ 86 GT T-tops

08-01-2002, 03:04 PM	#12
LOCASH Registered Member Join Date: Oct 2000 Location: Santa Lucia di Budoia, Italy Posts: 217	I replaced the cap and it hasn't happened since. Thanks to all of you for taking the time to help a stranded Stanger. I really appreciate it. __________________ 86 GT T-tops

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