Coolant in Intake Manifold
09-01-2017, 06:37 AM
#1
Registered User
Thread Starter
Coolant in Intake Manifold
My 1990 22re 4x4 pickup started idling high and surging when I applied the brakes the other night. I was pretty far from home so I continued with my commute about half way home the temperature guage started getting towards the red. I stopped at a gas station and filled my coolant which was very low. It stopped surging the rest of the way home but it still wasnt cooling down that much.
Yesterday I started pulling stuff apart and checking for vacuum leaks and checking everything to figure out why the truck was surging. I took off the intake hose and there was some moisture collected inside around the throttle gate (not alot) and it was very grimey. I cleaned that hoping that might stop the surging (i couldnt find any vacuum leaks or anything else and I couldnt check the IACV because a screw was stripped and it required taking off the intake.)
I also decided to replace the thermostat thinking that might be the cause of the overheating and could narrow down whether or not my waterpump was bad.
I fired the truck up and after adjusting the idle screw in it and lowering the idle speed it seemed to be running fine. I let the truck run for 15 minutes keeping an eye on the temperature gauge and it seemed to be doing fine. After the motor warmed up it still surged when applying the brakes. I was waiting on my roommate to come out to test the brakes so I could check the vacuum hose running from the booster when the trucks idle started to slow then died and wouldnt fire back up.
Trying to narrow down the problem I decided to take the intake hose off and run it without, thats when I saw all of the milky coolant...it was in everything. It was in the airbox, I pulled the intake manifold and it was in the lower intakes. I immediately pulled the oil plug and a ton of oil/coolant chocolate milk started pouring out.
I ordered a new IACV and pulled the intake to completely clean it.
Do you guys think the IACV is the issue here? Should I be looking/replacing something else? Do you think IACV was also causing the surging and replacing will solve both problems?
Thanks for the help!
Yesterday I started pulling stuff apart and checking for vacuum leaks and checking everything to figure out why the truck was surging. I took off the intake hose and there was some moisture collected inside around the throttle gate (not alot) and it was very grimey. I cleaned that hoping that might stop the surging (i couldnt find any vacuum leaks or anything else and I couldnt check the IACV because a screw was stripped and it required taking off the intake.)
I also decided to replace the thermostat thinking that might be the cause of the overheating and could narrow down whether or not my waterpump was bad.
I fired the truck up and after adjusting the idle screw in it and lowering the idle speed it seemed to be running fine. I let the truck run for 15 minutes keeping an eye on the temperature gauge and it seemed to be doing fine. After the motor warmed up it still surged when applying the brakes. I was waiting on my roommate to come out to test the brakes so I could check the vacuum hose running from the booster when the trucks idle started to slow then died and wouldnt fire back up.
Trying to narrow down the problem I decided to take the intake hose off and run it without, thats when I saw all of the milky coolant...it was in everything. It was in the airbox, I pulled the intake manifold and it was in the lower intakes. I immediately pulled the oil plug and a ton of oil/coolant chocolate milk started pouring out.
I ordered a new IACV and pulled the intake to completely clean it.
Do you guys think the IACV is the issue here? Should I be looking/replacing something else? Do you think IACV was also causing the surging and replacing will solve both problems?
Thanks for the help!
09-01-2017, 10:20 AM
#3
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I'm with L5wolvesf; you have all the symptoms of a blown head gasket. You're not going to get that much oil-water mixing with just something like the IACV. Yes to the compression test, but your problem is a coolant to cylinder leak, which doesn't always cause big compression loss.
Just so you know, fuel injected engines can't run with the intake hose off. (Air flow is measured in the VAF.) In your case, it also shuts off the fuel pump.
Just so you know, fuel injected engines can't run with the intake hose off. (Air flow is measured in the VAF.) In your case, it also shuts off the fuel pump.
09-01-2017, 10:27 AM
#4
Registered User
I'm with L5wolvesf; you have all the symptoms of a blown head gasket. You're not going to get that much oil-water mixing with just something like the IACV. Yes to the compression test, but your problem is a coolant to cylinder leak, which doesn't always cause big compression loss.
09-01-2017, 10:40 AM
#5
You can test the air valve by pressurizing the water jacket.
Also worth noting a gasket failure doesn't always show up on a cylinder compression test, wether it's done hot or cold. Take for example my last one where the gasket formed a one way valve, of sorts, the compression was not escaping but once the water got up to temp/pressure it would push its way thru.
Also worth noting a gasket failure doesn't always show up on a cylinder compression test, wether it's done hot or cold. Take for example my last one where the gasket formed a one way valve, of sorts, the compression was not escaping but once the water got up to temp/pressure it would push its way thru.
