Checking Vacuum Leaks - should i Use Carb Cleaner of WD40

simpsons721 · 12-22-2008, 09:26 AM

Im going to check some of my vaccum hoses for leaks

should i use wd40 or carb cleaner

all i know about checking for leaks is spray on the hoses and listen to the idle

is the noise a noticeable noise that you cant miss

also what does the liquids actually do by bean on a cracked hose

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wardriver · 12-22-2008, 09:34 AM

Do you have a propane torch? You can run an unlit propane torch with the valve cracked open over the suspected hoses while your engine idles. If you pass it over a hose and it idles up and take the torch away and it idles down - the replace that hose. The propane going in the system will correct the Air Fuel ratio causing it to idle up.

thook · 12-22-2008, 09:43 AM

Neither. Starting fluid is the thing to use. On the other hand, I've had vac leaks in the past and starting fluid didn't help track it down at all.

A propane torch is good because it will "smoke", so to speak. The air from the vac leak causes the gas to condense and appear as smoke. On the other hand, see above paragraph......third sentence.

The best thing, if neither of those methods work.....and you still suspect a vac leak, is find a mechanic with a vac leak detector. It purges smoke into the vacuum systems and smoke will pour out wherever the leak is. I had one at the cold start injector I couldn't find, and that found it in about 3min's......long enough for the smoke to fill the upper intake.

Oh, sometimes clamping all the hoses off.....one by one....at the source or termination of the line will do the trick. You've cut off the leak and the motor will either smooth out/speed up or slow down, depending on the behavior the suspected leak.

simpsons721 · 12-22-2008, 09:48 AM

i may try the propane trick (doesn't sound safe)

right now my truck idles at 600 rpm 750 is normal

i throw the egr code

i know some of my hoses are a little cracked so im gonna eliminate that problem

also i need to check my egr with a vacuum pump

i can also try starting fluid ill figure it out any other tips

atistang · 12-22-2008, 09:51 AM

you can use a flammable brake cleaner also, carb cleaner can sometimes eat at rubber so its not the best thing to use

starting fluid is what i always use

thook · 12-22-2008, 09:56 AM

Brake cleaner will erode hoses, too....

wardriver · 12-22-2008, 10:18 AM

Quote:

Originally Posted by simpsons721

i may try the propane trick (doesn't sound safe)

I would wager that Carb Cleaner is more volatile than propane....

But with any of the aforementioned methods USE COMMON SENSE! (IE don't smoke or over spray on exhaust manifold or EGR valve tubes ect)

atistang · 12-22-2008, 10:54 AM

Quote:

Originally Posted by wardriver

I would wager that Carb Cleaner is more volatile than propane....

But with any of the aforementioned methods USE COMMON SENSE! (IE don't smoke or over spray on exhaust manifold or EGR valve tubes ect)

the only thing about propane is it will settle in valleys, so if an amount of it settles somewhere and gets ignited then its a very big flash

TNRabbit · 12-22-2008, 04:02 PM

Propane or MAPP gas works great. Used it successfully many times on multiple vehicles.

thook · 12-22-2008, 04:21 PM

Maybe I wasn't holding my mouth right.....

12-22-2008, 09:34 AM	#2 (permalink)
wardriver Registered User Join Date: Jul 2007 Location: 26.3 road miles from the AT (VA) Posts: 319	Do you have a propane torch? You can run an unlit propane torch with the valve cracked open over the suspected hoses while your engine idles. If you pass it over a hose and it idles up and take the torch away and it idles down - the replace that hose. The propane going in the system will correct the Air Fuel ratio causing it to idle up. __________________ Current Toyota -95' 4Runner - 3.0/AT - New HG - Yakima Rack - MT's - Hella's - GPS- Sat Radio - Onboard 120V Former Toyotas - 81' Trekker- 70' FJ40 - 76' FJ40 -72 FJ40 - 85 Hilux (ZERO options) Laptop CarPC Switch Mod \| DC to AC Inverter Switch Mod Staff Mod for nHunting.com a community forum for hunting/fishing/shooting Last edited by wardriver; 12-22-2008 at 09:35 AM.

12-22-2008, 09:48 AM	#4 (permalink)
simpsons721 Registered User Join Date: Mar 2008 Location: Boulder, Colorado Posts: 182	i may try the propane trick (doesn't sound safe) right now my truck idles at 600 rpm 750 is normal i throw the egr code i know some of my hoses are a little cracked so im gonna eliminate that problem also i need to check my egr with a vacuum pump i can also try starting fluid ill figure it out any other tips __________________ 94 4runner 2wd 2nd gen 3.0 V6 3VZE Auto Started this Forum AT 131,000 NOW AT 149,500 Miles I need all the help i can get i want to match the guy in the forum with the pic of 333,333 milege

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12-22-2008, 09:51 AM	#5 (permalink)
atistang Registered User Join Date: Nov 2006 Location: Ohio Posts: 283	you can use a flammable brake cleaner also, carb cleaner can sometimes eat at rubber so its not the best thing to use starting fluid is what i always use