Hissing EGR Valve

[Elantastic]

Good evening LEC,
So After a time away from the car, I got back to resolving issues .... due to some performance issues I thought I’d pressurise the turbo with about 1 bar of compressed air through the turbo inlet, and I got some hissing out of the oil dipstick which I think indicates some worm turbo bearings? I also got some hissing from the EGR valve which is near the throttle body. the hissing was coming from underneath the valve so couldn’t see but when I put my finger there and blocked part of the hole the hissing changed.
Has anyone had any experience of changing the egr valve or had similar hissing? I’m pretty sure there shouldn’t be any hissing coming from this valve?

Thanks all

[HJ2]

Can it be a vacuum leak ?
Never heard of an EGR valve leaking... but then again... It's a Lotus

[Elantastic]

It’s the valve which is operated by the Vacuum I have a feeling the diaphragm inside may have perished, I'm pretty sure if air is escaping from it then the valve cannot be controlled as intended but open to suggestions

[TorqueHorse]

Hey Elantastic,
Do you have access to a vacuum pump/gauge?
Since I have my engine out and exhaust manifold off, I tried to replicate your issue. I put pressure directly on the inlet of the EGR pipe and couldn't hear anything until I applied a vacuum to the EGR valve (opening the diaphragm) . I was also able to apply a vacuum and have it hold pressure at the valve, to check the integrity of the diaphragm. That would probably be an accessible test you could try, even with the engine in place.

[Simon_P]

I think that you are trying to pressurise the intake system in order to check for leaks.

Without knowing what the issue is or how how loud the hissing is it is difficult to offer suggestions. Keep in mind that the components usually have other pressures from a running engine.

Venting from the dipstick just sounds like blow-by - there is a crank case ventilation system when the engine is running only worry if you are blowing oil out of the dipstick or burning oil.

The turbo bearings are oil fed and under oil pressure they if worn they are more likley to leak in the other direction when there is no boots and fill the inlet with oil.

I think that the EGR valve is usually closed and is opened when the engine speed and manifold pressure are low so applying twice the normal boost pressure and it leaking into the exhaust doesn't mean an awful lot. It is easy enough to remove and check.

what is the problem that you are experiencing?

[Elantastic]

Thanks for the responses all, Unfortunately I haven’t got a Vacuum tester device thingy but I can say the hissing was constant and coming from the holes where the Diaphragm is, was the noise on yours just from the valve moving ? I think the fact there is constant air coming from the Diaphragm must mean it’s leaking and unless I’m mistaken the valve must be sealed for the vacuum to work ?

As for taking the valve off is it doable without taking the whole pipe out or would I have to remove a few components to get good access?

Thanks all appreciate the responses

[Elantastic]

I think that you are trying to pressurise the intake system in order to check for leaks.

Without knowing what the issue is or how how loud the hissing is it is difficult to offer suggestions. Keep in mind that the components usually have other pressures from a running engine.

Venting from the dipstick just sounds like blow-by - there is a crank case ventilation system when the engine is running only worry if you are blowing oil out of the dipstick or burning oil.

The turbo bearings are oil fed and under oil pressure they if worn they are more likley to leak in the other direction when there is no boots and fill the inlet with oil.

I think that the EGR valve is usually closed and is opened when the engine speed and manifold pressure are low so applying twice the normal boost pressure and it leaking into the exhaust doesn't mean an awful lot. It is easy enough to remove and check.

what is the problem that you are experiencing?

I was pressurising the system with 20 psi through the turbo inlet, and from that I could hear air escaping from the egr vacuum control valve, when I placed my finger Over one of the holes (illustrated in thenpicture not my egr vavle by the way) the sound changed. I feel as though the diaphragm must be damaged in some way.

[TorqueHorse]

was the noise on yours just from the valve moving ?

Yeah, it was dead quiet otherwise.

[Elantastic]

Thanks for the replies all, I think the damn thing is broken them could this be the cause of the elevated tick-over on start up and drop in performance?

[Simon_P]

Check the base timing and idle first. That will highlight any issues. If you can take a scan as it will give you an idea of what is going on.

[Elantastic]

Check the base timing and idle first. That will highlight any issues. If you can take a scan as it will give you an idea of what is going on.

I Did manage to check the base timing before I the pressure test...it was way off SJ Sportscars did it last it was set to 0 before TDC I understand it does go out a bit but by that much
Has anybody had the EGR valve off before? Was just wondering if I would need to replace the gaskets
Thanks all