91 4runner ps fluid burning?

[mattrm]

Hi;
My 4 runner has been really going through PS fluid. And recently it has started smoking real bad on startup and when i turn the wheel. I first thought head gasket from the smoke but i don't show any signs of that ie. overheating, water in the oil etc. just the smoke. I've heard somewhat about the vacuum or whatever it is could pull the fluid through my engine and that is what's burning.
Any ideas or thoughts would be much appreciated.

thanks,
matt

[Brian R.]

Is the smoke coming from the engine compartment, or out the exhaust?

[mattrm]

The exhaust and thanks for the quick reply.

[Brian R.]

It is likely that the smoke you see on start-up is burning engine oil being pulled into the combustion chambers through the valve seals. It may be something else that is caused by the engine working hard which makes the smoke appear again when you turn the wheel (rings?). I don't see any way the PS fluid is getting into the engine. Do a compression check.

As far as the PS fluid loss is concerned, check the PS lines and connections for drip leaks. The lines may be leaking or the connections may need to be torqued. I think the fluid loss is unrelated to the smoke.

[mattrm]

Thanks Brian,

I was told it could be the switch that went out on my ps pump. VSV? Is there any chance that it could be power steering fluid that is burning through my engine?

Thanks again,
Matt

[Brian R.]

I don't know if it is possible for PS fluid to get into the combustion, however, there is a known problem with fluid loss associated with the VSV valve.

http://members.cox.net/stacewilliams/ps-pump.htm

[mmcpeck]

There is absolutely no way at all that PS fluid could get into your engine, it's a completely isolated system, fluid goes from the pump to the steering box and back, that's it, has nothing to do at all with the engine. Same as brake fluid, it's a separate system.

The PS lines all leak on these older Toyota's, it could burn if it is leaking on something hot, and it could leak more when you turn the wheel and the pump pressurizes more fluid, it could leak out more onto something hot. Replace all of the clamps on you PS lines and it will stop.

Is the smoke out of your tailpipe blueish or white?

[mattrm]

Thanks,

and it is white with a very little blueish tint.

matt

[mmcpeck]

White smoke at cold start up is normal, as your running a rich mixture and therefore there is a lot of extra moisture in the exhaust, H2O is a bi-product of burning a carbon based fuel. This is why exhaust systems rot out from the inside when you do short trips and the water doesn't heat out of the exhaust pipes.

But anyway, once the engine warms up and you are running a leaner or stiochiometric mixture, most if not all of you white smoke should go away. That is of course unless you are burning water(coolant), in which case you will have a constant white smoke because the water never goes away, such as a head gasket problem.

If that's the case you will see your oil diluted with coolant and vice versa, look in your radiator cap and see if your coolant looks oily, but I think you mentioned that none of this is happening.

Are you losing coolant at all?

As was mentioned you could be seeing some oil burning on start up from valve guide seals, they dry out around the valve guides and until they get a little heat, oil in the head will fall right down them and into the combustion chamber. It's not all that uncommon and not that big of a deal, you could go forvever like that.

If it's constantly burning oil (blue smoke) then you could have ring problems and that could be an issue. But if it's just on startup, I wouldn't worry about it. Get some Auto RX and do a cycle through it, it will clean things up and may even help seal up the valve guide seals.

[supremecourt07]

I have a 1991 4Runner and actually although it seems that the steering system is self-contained, there is a weak spot in the system that can cause steering fluid to leak into the intake manifold. There is a vacuum sensor that connects directly into the housing of the steering pump that is designed to bump up the RPMs when the steering system is under a load with low RPMs. There's a rubber membrane in that vacuum switch that, if it goes bad, can actually rupture and then allow steering oil to be sucked up through the hoses into the intake manifold. This is exactly what happened to my truck. I was constantly low on steering fluid but with no visible leaks and I'd get white smoke every once in a while. I talked to the guy at Toyota and said this is a chronic problem with these years of 4runners. I paid $100 to get a new vacuum switch from Toyota and easily installed it. Problem solved- no more steering leak and no more white smoke!

[Moppie]

Originally Posted by supremecourt07

I have a 1991 4Runner and actually although it seems that the steering system is self-contained, there is a weak spot in the system that can cause steering fluid to leak into the intake manifold. There is a vacuum sensor that connects directly into the housing of the steering pump that is designed to bump up the RPMs when the steering system is under a load with low RPMs. There's a rubber membrane in that vacuum switch that, if it goes bad, can actually rupture and then allow steering oil to be sucked up through the hoses into the intake manifold. This is exactly what happened to my truck. I was constantly low on steering fluid but with no visible leaks and I'd get white smoke every once in a while. I talked to the guy at Toyota and said this is a chronic problem with these years of 4runners. I paid $100 to get a new vacuum switch from Toyota and easily installed it. Problem solved- no more steering leak and no more white smoke!

That is an awesome find.
I wonder if it effects other Toyota's from the same era?

Thanks for posting it too

[fourwd1]

That sensor is for the Toyota Progressive Power Steering System. When the diaphragms go bad the vacuum sucks the PS fluid out to be burned.
You can cap off the 2 vac lines and be done with it, or replace the switch.