TOPIC: How difficult is it to replace gaskets and.....

Fixing vacuum leaks? Also how expensive is it? I've been reading Ron's articles on finding vacuum leaks and replacing gaskets. I would love to do this on my own to save money and learn a lot from my engine. But at the same time I don't have any money right now. Well not until my tax return is processed or I find a full time job. Whichever comes first.

Can someone explain to me how easy or difficult is it to do and if it's really expensive to do or cheap. Has anyone here taken their vehicle to a repair shop and had the really tough gaskets replaced? If so, how much was it? What I always try to do is find the parts myself then have the shop do it. I was wondering how much will it be for them to find vacuum leaks. I bet it's not something they do everyday. So when I ask them if they can do that to my vehicle I would probably get some confused looks. I'm hoping the shop I pick already knows what to do regarding vacuum leaks.

If you have done anything with replacing gaskets and/or vacuum leaks. Please let me know or anyone else that reads the forum know. Thank you.

Most vac leaks are quite easy to find and to repair, once you've found them. There are a number of techniques, depending on what you're looking at.

Vac hose and caps are cheap and readily available off the shelf. The most expensive (and potentially most harmful after the PCV) is the brake booster. That part is easily $100 should it be found blown, so let's just pray it's good!

One good indication of the booster being bad is rust and/or mottled paint on the booster below the master cylinder. This indicates your master cylinder has been leaking for quite some time. When it leaks, it leaks first into the booster. Once that has been happening for some time, it then begins to leak on the outside, destroying the paint.

The thing is the diaphragm is not made of something that resists brake fluid. More brilliant engineering from the auto companies!

Hope this helps make you feel more confident!

Hi Juan, my answer is: It depends...

Depends first on your knowledge & experience, then on your tools. The easy leaks to fix are the vacuum hoses that connect to intake manifold vacuum. If you've never touched any vacuum hoses, go to an auto parts store. Locate the vacuum hoses they have, usually in varying sizes on bulk spools on a rack. Grasp and feel the hoses check out the cut ends. See how new rubber hose feels and looks? When you compare this to what is on your car you have something to compare to.

Old vac. hose can get dry brittle split. Or can be oil soaked and soft. Or just hard. A good hose will seal firmly on its nipple fitting. If it just about falls off I'm suspicious. Hard plastic vac. hoses get brittle too (Ford). They can be patched w/ rubber ones to fix breaks.

A small leak in any hose will produce a rough idle, can cause misfires, hesitation, lean codes on a scanner and engine trouble codes in car computer. You really need to use your ears and all senses to feel how engine runs especially at idle. Put a hand somewhere on top of engine...is it smooth does it shake or vibrate?

If it runs smooth, then find a vac. hose to intake manifold ( a small one) pull it off temporarily. see how it runs now? There's the old carb. cleaner trick, spray a bit around hose connections and the intake gasket parting line, watch for any reaction, like a rough idle smoothing out for a few seconds. That is telltale reaction.

Thing is to check ALL vac. hoses condition and connections, some are harder to find/trace. I take attitude ALL are guilty till proven good. Remember Groove amplifies/intensifies vacuum levels in intake manifold making leaks worse.

As far as replacing intake gaskets etc., well IT IS do-able but first get to a library Reference section find repair books for your vehicle study and photocopy the whole part about replacing the intake gasket or whatever. You need proper tools.

If an intake is coming off need lots of clean rags/ towels paper towels etc for cleaning and to stuff in intake ports in the head(s) and lifter valley if needed to keep crud old gasket material etc from going into engine. Old toothbrushes, a gasket scraper, carb. cleaner,laquer thinner, Scotchbrite pads(go easy w/ those on Aluminum!) a sharp putty knife shop vacuum cleaner--stuff like that--is useful while changing intake gaskets. Get the gasket surfaces CLEAN but dont gouge or deeply scratch them. It is 3 part operation 1. Removal 2 Cleaning gasket surfaces till rag and finger come off the metal clean, 3. reinstall/reassembly. Often you must drain anti-freeze into something suitable before starting to pull an intake manifold. Clean any spills or rinse down w/ water. Keep the saved antifreeze Away from kids/pets.

Dogs& cats will drink it it will cause an awful slow agonizing death for them while breaking your heart--been through that one--sniff!

That whole thing again depends on your experience knowledge tools and location if you are going into a more involved repair. Got any buddies around who know/can help?

And lastly what are you working on? ( I can't remember)

Hope this helps.

Tracyg Gadgetman Reno

Gasket can be cheep, a milk carton , tetrabric can be used in many cases, place ontop of wher it shuld go and gently with the handel of a screwdriver knock on the border edge and it will shape and cut the circomference of your new gasget. It also marks all edges. could use some feltip pen on the throttel body base and get a print on the gasget use sicorros or cutter or something sharp to cut it out.
Plugs for vac lines cork from a bottle of vine maybe. I bought a set of 50 caps different sizes, only to find out that they last under a year before they crack and they where from a preformance shop costing over 50 dollars!!!
vacum tubes cut and blocked with the button of a pen or so seemd like a good idea until that cracked to. I think the rubber breakes when forcing it. the fit schuld be very good. Ive used pop cans alluminum to repare exsaust pipe, eh hehe
Other wise some gaget sillicone in a tube can be a gasget and might be good enoughf to fix old vacumlines.
It can be done in all the ways obiosly some better then others, Best wishes from me,

Hi Juan,

As has been said already, some gaskets are easy, some harder, and some, as a mechanic myself, I don't like to do. The bottom line is your trying to seal up vac leaks.

What kind of car do you have? I have access to on-line repair manuals and might be able to help. Older vehicles used more rubber vac lines than they do now - more things are controlled electronically vs. using vac signals. To find vac leaks around intake gskts, throttle body gskts, or anywhere outside air could get in AFTER the throttle body, use Carb Cleaner around areas in question, while the engine is running at idle. If the engine rpm's change, go up, you have found a leak - the carb cleaner is getting sucked in at the point of the leak and "richening" up the fuel mixture.

A quick lesson on gaskets. For many years, they used thinner gskts made of a metal core and fiber outer coating. Now they use a thicker plastic base with rubber inserts where the sealing takes place. As your engine components expand and contract - hot and cold - from below 0 deg to over 200 deg., aluminum components, plastic components and cast iron components might/will cause these newer plastic gsts to distort and the rubber inserts might shift. As a GM mechanic, I have seen meny of these gskts leak vacuum and coolant.

Hope this helps. Let me know what kind of vehicle you have and I will help you as I am able.


Scott Castleberg
Gadgetman Michigan

@Scott:

Thanks again for the quick feedback. I own a 2008 Mazda Tribute I model. It's a 4-cylinder 2.3 liter engine. It's not a hybrid. Just the base model. I've been researching on the Interwebz and I'm a bit leery on spraying carb cleaner on the engine. The only reason I'm leery is because it may catch fire from what I read. Maybe I should spray it before I start driving it for the day.

Is there any to minimize the risk of a fire on my engine? It's the only vehicle on our household. So if I burn the car I'll be in the doghouse for sure.

Also where should I spray the carb cleaner on my engine?

Thanks for the lesson on the gaskets. Anyway to get the better gaskets for my vehicle?

Hi Juan,

Thanks for the info on your vehicle. Sounds like you have a relatively new vehicle. I will look tonight or tomorrow for issues on your Mazda. If you DO use carb cleaner and are concerned about fire, use it on a cold engine. Once I get more info on your engine, I will recommend where the carb cleaner might be directed.

Scott


Just looked on-line. Your engine uses 4 large rubber "O-rings" between the plastic intake runners and the cylinder head. Where the 4 "tubes" meet the aluminum head is where I would use the carb cleaner. You don't have to use much. Hope this helps.

Scott