coolant surge tank cap??
Thread Starter
Le Mans Master
Joined: Jan 2009
Posts: 7,767
Likes: 19
From: East Texas
coolant surge tank cap??
should your cap on the coolant tank bleed any air/pressure after a long drive? car never got over 180* it was burping coolant but it was over full so i took some coolant out now it just bleeds a little pressure after i turn the motor off? is this normal for these cars? just had a drain and refill could it be air pockets comming out?
im worried its a head gasket leak
im worried its a head gasket leak
Thread Starter
Le Mans Master
Joined: Jan 2009
Posts: 7,767
Likes: 19
From: East Texas
The symptoms would indicate an exhaust leak through the head gasket into the cooling system. Any coolant in the oil?
Coolant should expand into the reservoir, then return to the radiator during cool-down. No over-flow.
Seems like exhaust gases are expelling coolant, and preventing a return siphon.
Pressurizing the block will confirm a head gasket leak.
With the temp not exceeding 180, that is not consistent with exhaust gases in the cooling system. Your temp should rise rapidly as the hot gases enter the cooling system. There may be a break in the 'closed system' preventing a siphon during cool-down, and the coolant keeps building in the surge tank. Check hose ends, clamps, cap gasket, etc. that would allow air into the cooling system.
Coolant should expand into the reservoir, then return to the radiator during cool-down. No over-flow.
Seems like exhaust gases are expelling coolant, and preventing a return siphon.
Pressurizing the block will confirm a head gasket leak.
With the temp not exceeding 180, that is not consistent with exhaust gases in the cooling system. Your temp should rise rapidly as the hot gases enter the cooling system. There may be a break in the 'closed system' preventing a siphon during cool-down, and the coolant keeps building in the surge tank. Check hose ends, clamps, cap gasket, etc. that would allow air into the cooling system.
Thread Starter
Le Mans Master
Joined: Jan 2009
Posts: 7,767
Likes: 19
From: East Texas
that makes me feel better, level goes down when its cool and there is no pressure when i remove the cap after cool down. now it just hisses out the cap after a 10 mile drive but only for a min. after i kill the motor??
Thread Starter
Le Mans Master
Joined: Jan 2009
Posts: 7,767
Likes: 19
From: East Texas
Instructor
Joined: Dec 2009
Posts: 147
Likes: 4
From: Chandler AZ
Coolant
Ran into a similar issue with my 2003 recently.
The car had been sitting in the garage for about 5 days from the last drive. I happened to open the hood and noticed that the top radiator hose was collapsed.
I opened the coolant tank cap and got a "hiss" out of it and the hose popped back into shape. Stange I thought.
It happened a second time about a week later.
I replaced the cap. The new cap, an AC Delco piece specified for the car is a slightly different design and has a higher pressure rating (from 15 to 18 pounds). Since the new cap, no more issues.
The cap seems to vent to the atmosphere through a diaphram in the center. I'm guessing that something clogged it up and wouldn't allow it to vent pressure. Then when it cooled down it wouldn't allow air back into the tank, causing the hose to collapse.
Ken Edney
Chandler, AZ
The car had been sitting in the garage for about 5 days from the last drive. I happened to open the hood and noticed that the top radiator hose was collapsed.
I opened the coolant tank cap and got a "hiss" out of it and the hose popped back into shape. Stange I thought.
It happened a second time about a week later.
I replaced the cap. The new cap, an AC Delco piece specified for the car is a slightly different design and has a higher pressure rating (from 15 to 18 pounds). Since the new cap, no more issues.
The cap seems to vent to the atmosphere through a diaphram in the center. I'm guessing that something clogged it up and wouldn't allow it to vent pressure. Then when it cooled down it wouldn't allow air back into the tank, causing the hose to collapse.
Ken Edney
Chandler, AZ
