Dealer says new intake gasket, how can he tell?

[89notch+65coupe]

The dealer ran a scan on my engine and said it needs a new intake gasket. How can he tell? I can't imagine there is a code for that. I'm guessing it is running lean and he is taking a guess. But I would think the dealer would know.

This is for my 97 Cougar, but it is a 4.6.

 

[RedBullitt]

never can tell with a dealer... lol has to be throwing some code (unless he actually looked at the intake) that is normally associated with a leak there etc. I dont know your dealer, so i cant knock him, but ill tell you i dont trust the ones around here one bit. Kinda funny, but scary: dads work truck, tranny swap, they didnt finish bolting it in= made it about 10 ft off the lot and got a big mess.... 2. backwards sepenentine belt on can=big mess and pia 3. all kinds of good stufff

 

[Dragstr05]

Easily. I dont know what code number exactly, but your fuel trims may be way high, indicated alot of fuel is being added, which means there is extra air getting in somewhere (most likely anyway). An intake gasket is a very reasonable way for a vacuum leak. This can be verified by visual inspection, or with a spray or smoke machine. There may be more ways, but those are the ones I know of.

 

[Shiroelex]

I usually blast some propane around the engine compartment, while the engine is running. Whenever I get to a spot with the propane that makes the idle change at all, odds are there is a leak there.

I'll bet that this one particular vaccum tee is pinched flat on your car. Take a look on the rear passenger side of the engine; there will be a 3/8ish vaccum tee, with a few plastic lines plugged into it. One of the lines runs under the throttle body. Almost every single MN12 with a 4.6 I have worked on, has had this rubber tee sucked flat, and it caused issues with fuel trim and whatnot.

 

[Mike97gt]

no scan tools can point out the difference from the engine running lean due to a intake gasket leak or from a vacumm leak from the lines, thats impossible. I find it funny when customers think we have equipment we hook up and it points to what to fix..

codes will not point out a intake leak by name, what happens is you get a p0171,p0174 lean code and then you have to use your brain and go through the stuff that can cause those codes..

most common is a vacumm leak from damaged vacumm lines or simply lines that fell off. second most likely is a bad maf, I have even seen a few that the PCV valve was the cause ( this was common on the 2.0 SPI escorts) the least likely is a bad intake gasket. Anything that allows unmetered air to enter the engine can cause these codes.

Many techs of questionable skill will just sell the intake gaskets and then fix any vacumm hoses they see damaged as they go. Sometimes this is easier than pinpointing a small air leak.

 

[89notch+65coupe]

Ya, the car runs fine as far as I can tell. I gave more money to that dealer than I should have anyway when they replaced the RR wheel bearing for $350 (had little choice). They wanted around $1000 for the intake gaskets and I politely said nope. But scamming customers does not seem like something dealer repair shops are known for.

I will check out the vacume lines. I am guessing whatever the reason it is due to the rats that sleep on the block in the winter. They leave their leftover dinner there too, so anything is possible.

 

[mity2]

I usually blast some propane around the engine compartment, while the engine is running. Whenever I get to a spot with the propane that makes the idle change at all, odds are there is a leak there.

LOL good old mechanic's trick.

Did the wonder when i was trying to figure out if intakemanihold gasket was leaking or not on my LT-1(well, with LT-1, thats pretty much given )

 

[Gearbanger 101]

They wanted around $1000 for the intake gaskets and I politely said nope.

I wouldn't have even been polite about it. I would have told him he was out of his ****ing mind.....so what's that...$50.00 for the gaskets and 12hrs labor to change them? Changing the intake gaskets on a 4.6L is about 45min to an hour job, maximum and one of the easiest things to do. Also...I've never seen an intake gasket on a 4.6L go bad yet. He's talking out of his hat, hoping to get you to bite.

Your car is way out of warranty. Take it to a more reputable source to have it worked on from now on. Word of mouth is often the best way to find them.

 

[Mike97gt]

scamming customers does not seem like something dealer repair shops are known for. .

Not trying to make fun of you but

I have been a dealer tech for a long time let me tell you, you have to be very very very careful about being ripped off both at private shops and at dealers.

I could go on for hours about the stealing that goes on at both types of shops.

Here is a good example..

2002 explorer with 85k on it comes in out of warranty with the customer concern being a noise from the rear while driving.. One of our hack thieves diaged it as being the rear end, so he sells the customer the entire independent rear end housing with all the internals came out to over 1800 bucks in parts and 6 hours to install it so it was about $2300 total.. This idiot does not show up for work so I get the job when the rear end comes in.. As I am driving it in the shop I hear the noise and right away I KNOW it's a rear wheel bearing that is not part of the diff on the independent suspension cars.. I put the truck on my lift and sure enough the left rear wheel bearing is so loose I can move the wheel in and out with my hands..

I call the foreman and asst. service mgr over and show it to them ad tell them the rear end is not the problem.. Well you know what they told me... " just put the rear end in and we will pay you to do the wheel bearing too" I am like WTF!!!! that customer is going to pay over two thousand bucks for something that is not broken!!!!! they told me that too bad the guy already bought it.. So I had to replace a perfectly good rear end and then fix the car...

Well anyways I have the 31 spline 8.8 limited slip carrier with 3.73's for sale if somebody is interested?? I know for sure that they were fine since they came out of that truck.

 

[ToplessStang]

Funny I just worked on a 97 Cougar 4.6L yesterday with lean codes. Bad maf. Baro was at 130HZ with no sign of a vacuum leak anywhere.

The only vehicule I wouldn't have trouble believing it is the intake gaskets is on a 99+ 3.8L Windstar. Those are quite common. The freeze frame data can give SOME clues to what is causing the lean conditon. On the Windstar it is always during warm up. I've never seen a intake gasket causing lean on a 4.6L.

 

[Mike97gt]

Funny I just worked on a 97 Cougar 4.6L yesterday with lean codes. Bad maf. Baro was at 130HZ with no sign of a vacuum leak anywhere.

The only vehicule I wouldn't have trouble believing it is the intake gaskets is on a 99+ 3.8L Windstar. Those are quite common. The freeze frame data can give SOME clues to what is causing the lean conditon. On the Windstar it is always during warm up. I've never seen a intake gasket causing lean on a 4.6L.

I agree bad maf or a vacumm leak from a vaumm line is common but not the intake gaskets.. I have never seen intake gaskets go on a modular motor..

BTW those 99+ windstar instake go all the time, I have made so much money on them it's not even funny. I can do the 6 small gaskets the cover gasket, the bolts, the little vac line and the valve cover in under a hour. without the valve cover I have done them in 15 minutes. We get 4 hours for them cash what do you guys get?

 

[Mustang5L5]

Run to autozone and have them run the codes. Write down the numbers they give you, ignore their diagnostics and then post up the numbers here and we can continue from there.

Also, a good way to find vac leaks in the engine bay is to spray carb cleaner around the engine bay. It will cause the idle to jump up slightly when you find a leak. It's a bit easier to manage in an engine bay than propane since you have a spray can

 

[ToplessStang]

I agree bad maf or a vacumm leak from a vaumm line is common but not the intake gaskets.. I have never seen intake gaskets go on a modular motor..

BTW those 99+ windstar instake go all the time, I have made so much money on them it's not even funny. I can do the 6 small gaskets the cover gasket, the bolts, the little vac line and the valve cover in under a hour. without the valve cover I have done them in 15 minutes. We get 4 hours for them cash what do you guys get?

1.5 hrs but the time it takes us doesn't affect our salary. Just gets the boss on your AZZ if your slow.

 

[Mike97gt]

1.5 hrs but the time it takes us doesn't affect our salary. Just gets the boss on your AZZ if your slow.

Ohhh we are flate rate, so I make lawyer money while I am doing those.. 4.0 hours in under 45 minutes = lawyer money

 

[Will Smith]

I usually blast some propane around the engine compartment, while the engine is running. Whenever I get to a spot with the propane that makes the idle change at all, odds are there is a leak there.

I'll bet that this one particular vaccum tee is pinched flat on your car. Take a look on the rear passenger side of the engine; there will be a 3/8ish vaccum tee, with a few plastic lines plugged into it. One of the lines runs under the throttle body. Almost every single MN12 with a 4.6 I have worked on, has had this rubber tee sucked flat, and it caused issues with fuel trim and whatnot.

I would try this trick but instead of propane use some carb cleaner it will vary the idle when a leak is found so make sure she is good and warm and idling smooth.