Upper intake manifold gasket leak

[02cammy]

Hello today I took my car to the dealer to find out why my 02 camaro 3.8 has been getting horrible mileage, 10.9 to be exact. Everywhere else I took it to couldn't find the problem do I broke down n took her to the dealer.. Anyhow they said I have a leaky upper intake manifold gasket.. Could that be the reason y my mileage is so bad considering I've changed the following, calatlytic convertor, new o2 sensor, knock sensors?

[thcardoc]

That can cause some driveability concerns especially with idle quality, but it would not have anything to do with a fuel mileage issue.

Exactly how are you calculating your fuel economy?
How many miles per trip do you normally travel?
How many of those are highway miles, and at what speed?
How much stop and go traffic do you normally encounter?
Are there any other issues with how the car is running?
Can you list any codes that are setting?

[02cammy]

Oh great I just spent money for nothing then.. They told me it would improve the mileage but couldn't say how much.. Thanks for letting me know I got ripped off

[thcardoc]

Originally Posted by 02cammy

Oh great I just spent money for nothing then.. They told me it would improve the mileage but couldn't say how much.. Thanks for letting me know I got ripped off

If the ONLY problem was a fuel mileage concern you may be correct, but if there was anything else going on then it very easily was a necessary repair and not a rip-off or wasted money. From the simple question of will an intake gasket issue cause a fuel mileage complaint to get all the way to potentially being ripped off without any technical details to support the assumption is IMO careless. It's likely you only talked to a service writer who has no more of an idea of how to diagnose and repair your car than you do. That person could guess wrong while he/she tried to answer your mileage question when you asked it.

I'll ask again, what were the symptoms that led to the diagnosis of the intake gasket failure? FWIW, that gasket failing is quite common but causes a different set of drivabilty symptoms.

[02cammy]

Originally Posted by thcardoc

If the ONLY problem was a fuel mileage concern you may be correct, but if there was anything else going on then it very easily was a necessary repair and not a rip-off or wasted money. From the simple question of will an intake gasket issue cause a fuel mileage complaint to get all the way to potentially being ripped off without any technical details to support the assumption is IMO careless. It's likely you only talked to a service writer who has no more of an idea of how to diagnose and repair your car than you do. That person could guess wrong while he/she tried to answer your mileage question when you asked it.

I'll ask again, what were the symptoms that led to the diagnosis of the intake gasket failure? FWIW, that gasket failing is quite common but causes a different set of drivabilty symptoms.

Well the drive ability symptoms are vibration on idle as it shudders at times. Not all the time but wen I'm sitting at idle it shudders every so often. My last full tank I only got 195mls for 16 gallons. So I told the service person of all that I've replaced and from what they've said the only thing they could find was a faulty intake manifold gasket leaking. A vacuum issue

[thcardoc]

Originally Posted by 02cammy

Well the drive ability symptoms are vibration on idle as it shudders at times. Not all the time but wen I'm sitting at idle it shudders every so often. My last full tank I only got 195mls for 16 gallons. So I told the service person of all that I've replaced and from what they've said the only thing they could find was a faulty intake manifold gasket leaking. A vacuum issue

Well the vibration or shudder at idle does open the door for the intake gasket leaking. That is a very plausible diagnosis for that.

Now 195 miles for 16 gallons, almost 12mpg. How much city driving (stop and go, or other excessive idling) is that, and how much of it was on the highway?

[02cammy]

Originally Posted by thcardoc

Well the vibration or shudder at idle does open the door for the intake gasket leaking. That is a very plausible diagnosis for that.

Now 195 miles for 16 gallons, almost 12mpg. How much city driving (stop and go, or other excessive idling) is that, and how much of it was on the highway?

It was about 50/50 city and highway and what I've been hearing from everyone that even if I only did city driving I should atleast get 17 with all the parts I have replaced

[thcardoc]

Originally Posted by 02cammy

It was about 50/50 city and highway and what I've been hearing from everyone that even if I only did city driving I should atleast get 17 with all the parts I have replaced

http://www.fueleconomy.gov/***/noframes/16500.shtml

Your mileage may vary of course. Getting good fuel economy isn't as easy as just changing a few parts. There are so many different factors to consider that it goes way beyond the scope of what we can do with this thread. But lets start by planning a little over the road trip maybe over the weekend. Fill up, then try and get about a 200 miler going a conservative 65mph maximum. Re fill and then post the results. Lets see what you get on the highway first, only run the accessories that have to be running.

[02cammy]

Originally Posted by thcardoc

http://www.fueleconomy.gov/***/noframes/16500.shtml

Your mileage may vary of course. Getting good fuel economy isn't as easy as just changing a few parts. There are so many different factors to consider that it goes way beyond the scope of what we can do with this thread. But lets start by planning a little over the road trip maybe over the weekend. Fill up, then try and get about a 200 miler going a conservative 65mph maximum. Re fill and then post the results. Lets see what you get on the highway first, only run the accessories that have to be running.

Ok thank you I'll give it a shot... Hopefully the repair fixes my problem. I get it back tomorrow since they made it an all day job.. I'm thinking about also replacing my injector seals just to be sure.. They are the originals and I have 147+ miles on the car.. Thanks for your help I'll let you know how it goes per the weekend of your curious

[thcardoc]

Originally Posted by 02cammy

Ok thank you I'll give it a shot... Hopefully the repair fixes my problem. I get it back tomorrow since they made it an all day job.. I'm thinking about also replacing my injector seals just to be sure.. They are the originals and I have 147+ miles on the car.. Thanks for your help I'll let you know how it goes per the weekend of your curious

The injector seals (lower) could cause a vacuum leak and potentially be an issue at idle, (rough idle, misfire, fuel trim correction) they would not cause a fuel mileage concern. The upper seals could cause a loss of fuel, but that would be quite evident as a fuel leak.

[02cammy]

Originally Posted by thcardoc

The injector seals (lower) could cause a vacuum leak and potentially be an issue at idle, (rough idle, misfire, fuel trim correction) they would not cause a fuel mileage concern. The upper seals could cause a loss of fuel, but that would be quite evident as a fuel leak.

Well Chevy still has my camaro because the tech found another gasket that needed to be replaced.. And the service girl said they are gonna replace it at no charge.. She couldn't tell me what gasket it was but hell a gasket is a gasket it can only be good

[02cammy]

Originally Posted by thcardoc

The injector seals (lower) could cause a vacuum leak and potentially be an issue at idle, (rough idle, misfire, fuel trim correction) they would not cause a fuel mileage concern. The upper seals could cause a loss of fuel, but that would be quite evident as a fuel leak.

I was told that the other gasket they replaced was my water jacket.. What is that and what's its purpose? I have been having heating issues on the highway with the temp going up n not down as it should with the wind

[thcardoc]

Originally Posted by 02cammy

I was told that the other gasket they replaced was my water jacket.. What is that and what's its purpose? I have been having heating issues on the highway with the temp going up n not down as it should with the wind

Hmmmm....

Look down and you will see that I asked these questions:
Exactly how are you calculating your fuel economy?
How many miles per trip do you normally travel?
How many of those are highway miles, and at what speed?
How much stop and go traffic do you normally encounter?
Are there any other issues with how the car is running?
Can you list any codes that are setting

The next to last one asked if there were any other issues, your engine temperature issue is something that I, and I'm sure the the dealers tech would have liked to know about in order to accurately troubleshoot your vehicles problems.

Now, I don't know what you are actually referring to when you identify a gasket as being a water jacket. But cooling system issues could cause altered ignition timing and fuel control maps and that could definately have an impact on your fuel mileage.