Intake Manifold Gasket Failure Symptoms

[SimpleChair]

So for the Last year or so I have been desperately trying to solve a fume intrusion into the passenger cabin that was making me sick every time I drove the car: headache, coughing, eventually fluid buildup in lungs, eye irritation, dizziness, metallic taste in mouth/lungs, was like a severe allergic reaction plus bronchitis. Many trips to mechanics and dealers found no exhaust leaks or other problems with the car, no engine codes, car otherwise runs fine.

I replaced the entire hvac system (although I found I didn’t need to, I was perplexed when I saw no leaks on the heater core or evaporator and my a/c refrigerant wasn’t leaking/kept vacuum fine).

I also thought it might be a fuel sending unit gasket leak with fumes coming out from the tank and making their way into the passenger cabin. (Could smell strong gas smell sometimes too)

It finally occurred to me to check the intake gaskets because I didn’t replace them when I did my driver side cylinder head. I was reading up about exhaust gas inhalation symptoms and all of the above match exposure to nitrogen oxide (different than nitrous oxide or nitrogen dioxide), which is recirculated through the intake by way of the EGR. When I took off the intake, I found oil around where the gaskets seat, and lots of exhaust gas debris. Definitely wasn’t sealed. Note that if it is not your intake gaskets, it could be your EGR is leaking. I have found other threads where people are desperately trying to figure this out because the car otherwise ran fine. Make sure to get new bolts from acdelco with the loctite on them when you do this repair, all-in probably $100 in parts and 2-3 hours of work at a leisurely pace. Plenty of online videos to explain the procedure. Hope this is helpful.

 

[Donal]

So for the Last year or so I have been desperately trying to solve a fume intrusion into the passenger cabin that was making me sick every time I drove the car: headache, coughing, eventually fluid buildup in lungs, eye irritation, dizziness, metallic taste in mouth/lungs, was like a severe allergic reaction plus bronchitis. Many trips to mechanics and dealers found no exhaust leaks or other problems with the car, no engine codes, car otherwise runs fine.

I replaced the entire hvac system (although I found I didn’t need to, I was perplexed when I saw no leaks on the heater core or evaporator and my a/c refrigerant wasn’t leaking/kept vacuum fine).

I also thought it might be a fuel sending unit gasket leak with fumes coming out from the tank and making their way into the passenger cabin. (Could smell strong gas smell sometimes too)

It finally occurred to me to check the intake gaskets because I didn’t replace them when I did my driver side cylinder head. I was reading up about exhaust gas inhalation symptoms and all of the above match exposure to nitrogen oxide (different than nitrous oxide or nitrogen dioxide), which is recirculated through the intake by way of the EGR. When I took off the intake, I found oil around where the gaskets seat, and lots of exhaust gas debris. Definitely wasn’t sealed. Note that if it is not your intake gaskets, it could be your EGR is leaking. I have found other threads where people are desperately trying to figure this out because the car otherwise ran fine. Make sure to get new bolts from acdelco with the loctite on them when you do this repair, all-in probably $100 in parts and 2-3 hours of work at a leisurely pace. Plenty of online videos to explain the procedure. Hope this is helpful.

Please add the vehicle year of manufacture and model.

 

[Fless]

Please add the vehicle year of manufacture and model.

It's in the signature.

 

[Blackcar]

What happens if you keep HVAC system in recirculate position.

 

[strutaeng]

I've seen a bit of blonde oil on the intake manifold gaskets when I've removed them on my trucks, but thought it was normal from the PCV. Again, a little not a lot. These are vehicles w/o EGR though.

I can't imagine leaking intake gaskets causing fumes inside the cabin though. The intake is under vacuum or negative pressure (sucks air in).

The EGR was deleted from the factory, I can't recall what year(s). I've never understood why; I think a slight cam profile or ECU calibration? Depending on where you are, some folks have deleted EGR. A block off plate and tune reflash. EGR can be problematic with valve failure and it does create more soot inside the intake manifold. But that's another topic.

 

[Joseph Garcia]

Welcome to the Forum from NH.

Lots of knowledgeable folks here who freely share their knowledge, experiences, and perspectives. Knowledge is power.

I hope that you will become a participating member in the Forum's discussions.

Pics of the truck, please.

You are already receiving clarifying questions from the knowledgeable folks on this Forum.