# Excessive pressure/air (exhaust?) in cooling system **URL:** \ **Category:** Maintenance/Repairs\ **Tags:** van, ram, dodge\ **Created:** [April 14, 2010, 1:11am UTC](https://community.cartalk.com/t/excessive-pressure-air-exhaust-in-cooling-system/47437 "2010-04-14T01:11:27Z")\ **Posts on this page:** 8\ **Page:** 1
**Author:** ![RAMblinmanOR](https://avatars.discourse-cdn.com/v4/letter/r/e99b99/32.png) [@RAMblinmanOR](https://community.cartalk.com/u/RAMblinmanOR)\ **Post date:** [April 14, 2010, 1:11am UTC](https://community.cartalk.com/t/excessive-pressure-air-exhaust-in-cooling-system/47437/1 "2010-04-14T01:11:27Z")
I have excessive pressure/air (exhaust?) in my cooling system, causing loss of atmospheric heat and engine overheating. I have been through the entire cooling system, replaced everything from the pump to the heater core over the past 18 mths. This particular problem began just before I replaced the heater core (about 3-4 months ago) and has been getting steadily worse. This past weekend, I replaced the intake manifold gasket. The problem is still there, so I tried running without the thermostat installed… Still lots of air. It seems obvious that the only thing it could possibly be is a head gasket, but this motor runs great, and there is no evidence of oil in the water or water in the oil. I see white smoke when cold at first startup, but it quickly stops, and there isn’t any water actually flowing from the tail pipe. Maybe a drip or two when cold. I am kicking myself for not just going ahead and doing head gaskets when I did the intake; I was half way there! Any ideas, advice, thoughts would be greatly appreciated! ---
**Author:** ![waterboy](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/waterboy/32/764_2.png) [@waterboy](https://community.cartalk.com/u/waterboy)\ **Post date:** [April 14, 2010, 1:41am UTC](https://community.cartalk.com/t/excessive-pressure-air-exhaust-in-cooling-system/47437/2 "2010-04-14T01:41:10Z")
Stab 1 at the cat, head gasket. ---
**Author:** ![RAMblinmanOR](https://avatars.discourse-cdn.com/v4/letter/r/e99b99/32.png) [@RAMblinmanOR](https://community.cartalk.com/u/RAMblinmanOR)\ **Post date:** [April 14, 2010, 2:13am UTC](https://community.cartalk.com/t/excessive-pressure-air-exhaust-in-cooling-system/47437/3 "2010-04-14T02:13:00Z")
I didn’t think of the cat, it started making a rattling noise right about when this all began. Do you think that could be it? If so, did it take out the head gasket? ---
**Author:** ![willey](https://avatars.discourse-cdn.com/v4/letter/w/a9adbd/32.png) [@willey](https://community.cartalk.com/u/willey)\ **Post date:** [April 14, 2010, 12:05pm UTC](https://community.cartalk.com/t/excessive-pressure-air-exhaust-in-cooling-system/47437/4 "2010-04-14T12:05:01Z")
Head gasket problem. You should have done them when you had the intake off. ---
**Author:** ![VDCdriver](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/vdcdriver/32/30_2.png) [@VDCdriver](https://community.cartalk.com/u/VDCdriver)\ **Post date:** [April 14, 2010, 12:36pm UTC](https://community.cartalk.com/t/excessive-pressure-air-exhaust-in-cooling-system/47437/5 "2010-04-14T12:36:48Z")
It sure sounds like a head gasket problem. ---
**Author:** ![RAMblinmanOR](https://avatars.discourse-cdn.com/v4/letter/r/e99b99/32.png) [@RAMblinmanOR](https://community.cartalk.com/u/RAMblinmanOR)\ **Post date:** [April 14, 2010, 3:59pm UTC](https://community.cartalk.com/t/excessive-pressure-air-exhaust-in-cooling-system/47437/6 "2010-04-14T15:59:34Z")
Yeah, I knew it when I was there… The cat never really entered my mind though, aside from having an annoying rattle. I was trying to get this cooling system dealt with first, little did I know that they were related (I read up on converters and reasons for failure last night). All the pieces are starting to fall into place. Thanks ---
**Author:** ![the\_same\_mountainbike](https://avatars.discourse-cdn.com/v4/letter/t/c89c15/32.png) [@the\_same\_mountainbike](https://community.cartalk.com/u/the_same_mountainbike)\ **Post date:** [April 14, 2010, 9:17pm UTC](https://community.cartalk.com/t/excessive-pressure-air-exhaust-in-cooling-system/47437/7 "2010-04-14T21:17:32Z")
You can find out for sure whether it’s the headgasket. Pick up a cylinder leakdown test kit at the parts store. Basically, you’ll us a fitting in the spark plug hole to pump air into each cylinder (with the valves closed) and monitor the pressure to see of the cylinder holds. But I gotta be honest, if you’re seeing bubbles coming up through the radiator cap hole with the engine running it’s a pretty safe bet that you have a breech in the head gasket. The bubbles are the combustion gasses getting blown through the breech and into the water jacket and migrating to the system’s highest point: the radiator cap hole. ---
**Author:** ![ok4450](https://avatars.discourse-cdn.com/v4/letter/o/e9bcb4/32.png) [@ok4450](https://community.cartalk.com/u/ok4450)\ **Post date:** [April 15, 2010, 12:25am UTC](https://community.cartalk.com/t/excessive-pressure-air-exhaust-in-cooling-system/47437/8 "2010-04-15T00:25:03Z")
A quick test for a head gasket leak is this; and keep in mind that it’s not 100% definitive but close enough. When the engine is stone cold loosen the radiator cap and release any pressure. Start the engine and allow it to idle for 15-20 seconds. Shut it off and quickly release the radiator cap. If you hear a hiss there is at least a reasonable chance of a head gasket breach. At that point further diagnosis is needed to verify it. (compression test, hydrocarbon test, vacuum gauge test, etc.)