I think I'm burning brake fluid through my engine. Possible?

[whyzee125]

Hey guys,

My 96 4Runner has been puffing a decent amount of white smoke on some cold starts for the 2 years I've owned it. Sometimes it feels a little rough for 2-3 seconds too, but it always clears right up.

I assumed head gasket like any normal person would, right? It gets weird though. I've lost exactly 0 coolant in 2 years, oil and coolant look clean, zero overheating, and the white smoke doesn't smell like coolant.

I've also been fighting a really soft brake pedal for 2 years. I've bled it a few times and it feels good for about a month, and is then super low on fluid again.

Lately, it's going through about half a quart of brake fluid per day with zero visible leaks. I pulled both drums and they're dry. All brake lines and fittings look good and there are no leaks around the MC.

I then noticed that if I leave the fluid level low, it seems to never have a rough/smoky start but if I top the fluid off, it does it again.

Is it possible for fluid to somehow be entering the booster and then burning through the intake system?

I watched a video on MC replacement on this truck and it doesn't look like there would be a way for it to leak into the booster without leaking outside of the MC but it sure seems like that's what is happening.

Any help is very appreciated. Btw the truck is a 96 limited with 205k miles on it.

Thanks!

 

[Bad Luck]

[MENTION=113401]whyzee125[/MENTION] It’s possible for the master cylinder to leak into the booster. Try pulling the vacuum hose and check valve to the booster and see if any fluid comes out. If nothing comes out try sticking a cotton swab into the booster and see if it comes back wet.

 

[whyzee125]

[MENTION=113401]whyzee125[/MENTION] It’s possible for the master cylinder to leak into the booster. Try pulling the vacuum hose and check valve to the booster and see if any fluid comes out. If nothing comes out try sticking a cotton swab into the booster and see if it comes back wet.

Thank you! I did try pulling the vacuum hose and nothing came out, but I'll try the cotton swab thing. It's pretty high up so makes sense nothing came out. I think this almost has to be my issue.

 

[spartacus]

Check the vacuum hose on the brake booster for brake fluid.The rear seal on the master could be leaking into the brake booster then getting sucked into the intake.

 

[brillo_76]

I am just watching this thread to see if brake fluid is actually getting sucked into the intake.

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[whyzee125]

Well I'm stumped again. I found that I have a small leak in a rear brake line but it's shooting the fluid upward and kind of on top of the gas tank, so that's where my brake fluid is going. I honestly can't tell if there's fluid inside the booster without removing the MC, I removed the hose and couldn't tell either way.

I'm going to replace the brake line and see if that stops my brake fluid from disappearing but I'm guessing that it will, and I'll still be left with the cold start smoke issue.

The really weird thing though, is it never does the cold start smoking and shaking if I leave the brake fluid empty? It's possible that it's coincidence because it only does it sometimes anyway but it's just really weird.

Being a 96, I think head gasket issues were fairly common so unfortunately that's probably what I've got going on. It's weird though because it's done this ever since I bought it and I've never topped up the coolant even once. Doesn't seem to have lost a drop. Oh well, I'll keep casually trying until it gets worse or I find something lol. I'll keep ya guys posted.

 

[brillo_76]

Very common to get a leak in a rear brake line. That's fun to sneak around the gas tank to put a new one in.

On the head gaskets. As long as your heads are level. The latest revision of oem will last.

The previous gen of this engine had the head gasket issues more then these do and that's good news.

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[shadow247]

Well I'm stumped again. I found that I have a small leak in a rear brake line but it's shooting the fluid upward and kind of on top of the gas tank, so that's where my brake fluid is going. I honestly can't tell if there's fluid inside the booster without removing the MC, I removed the hose and couldn't tell either way.

I'm going to replace the brake line and see if that stops my brake fluid from disappearing but I'm guessing that it will, and I'll still be left with the cold start smoke issue.

The really weird thing though, is it never does the cold start smoking and shaking if I leave the brake fluid empty? It's possible that it's coincidence because it only does it sometimes anyway but it's just really weird.

Being a 96, I think head gasket issues were fairly common so unfortunately that's probably what I've got going on. It's weird though because it's done this ever since I bought it and I've never topped up the coolant even once. Doesn't seem to have lost a drop. Oh well, I'll keep casually trying until it gets worse or I find something lol. I'll keep ya guys posted.

Are you losing coolant? Make a mark with a Dry Erase marker on the Coolant Tank for your COLD start level, and see if you are losing any coolant over a week. You can also get a Block Tester from the Auto Parts store that tests the coolant for combustion gases.

Finally, put a piece of WHITE paper in front of the exhaust, and see what is actually coming out of the exhaust on those cold starts. My guess is that it's nothing more than condensation that builds up in the muffler.

 

[brillo_76]

You can also do what they call a leak down test on the coolant system to see if pushing coolant into the cylinder. Your spark plugs can show you if they are burning antifreeze by their color. Not to mention a compression test too.

I agree, the rear line may solve your missing brake fluid issue and that is a good thing too..

 

[whyzee125]

Good idea on marking the coolant tank. It will definitely not show anything over a week--in 2 years it hasn't noticeably dropped. It was about 2/3 of the way up when I bought it and it still is, never topped it off. The amount of smoke is pretty significant some days, so while it could be condensation, it's way more than any other car I've had. If you leave it idling it'll puff smoke for 5 mins. It doesn't really have a smell aside from normal cold start exhaust. Definitely doesn't smell like coolant but it does misfire for 2-3 seconds if it's been sitting a while on some starts. Thanks for the advice, I'll try that out!

 

[brillo_76]

Maybe I missed it. Did you verify the plugs and wires are good? As wires will go bad. I have a link on my signature.

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[shadow247]

Good idea on marking the coolant tank. It will definitely not show anything over a week--in 2 years it hasn't noticeably dropped. It was about 2/3 of the way up when I bought it and it still is, never topped it off. The amount of smoke is pretty significant some days, so while it could be condensation, it's way more than any other car I've had. If you leave it idling it'll puff smoke for 5 mins. It doesn't really have a smell aside from normal cold start exhaust. Definitely doesn't smell like coolant but it does misfire for 2-3 seconds if it's been sitting a while on some starts. Thanks for the advice, I'll try that out!

You aren't losing coolant, then you need to look elsewhere. You could be burning Oil, or have an injector that is leaking on startup.

Even my 388k 3rd gen would blow some white smoke on cold foggy mornings. Never used a drop of coolant, but it leaked so much oil I never could figure out if it was burning it.

 

[whyzee125]

I changed the plugs a while back but haven't done the wires. Can't remember if they're original or not. Something interesting I found this week is that I seem to have a bad ground. I was having some weird electrical issues that I attributed to my dying alternator but a few of them remained after replacing it. It wouldn't start the other day and would just do the "tdtdtdtdt" noise like a dead battery but the battery was good. Replaced it just to be sure and same thing. I wonder if a weak ground could be causing my cold start misfire and the smoke is just extra fuel that isn't being burnt because it's idling so rough?

 

[brillo_76]

I changed the plugs a while back but haven't done the wires. Can't remember if they're original or not. Something interesting I found this week is that I seem to have a bad ground. I was having some weird electrical issues that I attributed to my dying alternator but a few of them remained after replacing it. It wouldn't start the other day and would just do the "tdtdtdtdt" noise like a dead battery but the battery was good. Replaced it just to be sure and same thing. I wonder if a weak ground could be causing my cold start misfire and the smoke is just extra fuel that isn't being burnt because it's idling so rough?

Yes I bad ground can be causing your issues or contributing to them.

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[Krils]

Also feel the entire master brake cylinder and the rubber bands under the reservoir, oil leakage may not be noticeable. Just as the oil seals are leaking oil from the engine, so here it may be leaking.