how difficult is it to clean a rattling valve?
I’m not aware that valves “rattle”, at least not the valves in the cylinder head. Cleaning the valves in cylinders is a matter of taking the motor apart, very expensive. There are fuel additives that “claim” to clean valves, but the claims could be more fiction than real. The gas we buy has additive to keep the fuel system clean and these days valve jobs due to carbon build up are rarely needed.
There are other valves in the car, PCV valves etc. so perhaps you are talking about something outside the motor. I think you need to investigate the cause of the “rattle”. Noises in the motor come from all kinds of sources.
You simply remove the head, remove the valve, mechanically clean the valve, grind the valve, grind the valveseat (valves and their seats “seat” and need to be resurfaced once disassembled), reinstall the valve, reinstall the head, and hope you didn’t screw up the valve timing. Of course you’ll need also to replace the headgasket, the timing belt, the valvecover gasket, etc. etc. etc.
What symptoms are you trying to fix?
I appreciate the help, because I’m not a car mechanic. I thought it might be something simple, like changing a wiper blade. The problem is, I have to bring the car in to my mechanic every few months to get this rattling noise fixed. He seems confused as well as to why this needs fixing so often. At one point he even cleaned (he said dropped) the fuel tank. Is there another theory as to why the valve gets dirty?
What valve are we talking about? In addition to the PCV valve that UncleTurbo mentioned, there’s an exhaust gas recirculating (EGR) valve that could need periodic cleaning…and if that one were sticking it could cause “rattling” (more correctly referred to as “pinging”).
If it’s the EGR valve, I have to ask if you’re burning oil…are you? The EGR valve passes exhaust gas to the intake and can get contaminated with carbon deposits.
Is the “rattling” happening when you accelerate?
As the others have said - you need to get a better description from the mechanic of what it is that they are saying the problem is and what exactly it is that they are cleaning.
This would be like a neophyte surgeon asking a more experienced surgeon for instructions on how to repair “the heart valve” (there are 4, if I recall correctly), or how to set “the bone” (there are lots of them), or how to repair “the aneurysm” (these can occur in many places in the human body).
I understand that pmalone’s car knowledge is limited, but without some clarification regarding which valve he/she is referring to, all that will result is a big mass of confusion for all concerned. Pmalone–ASK your mechanic which “valve” is rattling, and also ask what he does each time to remedy the situation.
The more I think about it, the more I expect the answer will be “the EGR valve”. But yeah, we need to know.
Sounds like my ticking, which a chemical cleaning has never completely solved and probably never will.
'92 Explorer 4.0 sounds like a ‘lifter ticking’. comes and goes, idling, driving, accelerating, or coasting.
Tech will put a cleaner in through the intake and the tick is gone for a week but it comes back.
The theory ( for mine ) is that it’s carbon, or other gunk buildup, on the neck of one or more valves much like the pictures in the shell gasoline tv ads. The existance of this buildup doesn’t allow the freedom of movement for the valve to quickly spring back up with each cycle so the rocker arm has space between at every revolution and ticks like a bad lifter.
I have not, and probably will not dis-assemble this engine for this problem and am looking closely at the $4500.00 I could get for it against a new Escape.
From what everyone has written, and from what my mechanic has described to me each time this has happened, I am sure we’re talking about the procedure described by “same mountain bike”, cleaning and grinding the valve. My question now is, what can I expect if I just ignore the sound? Is it a big deal if this is only one valve? Can I go for several months doing nothing?
I suspect he’s actually been cleaning the EGR valve. If he’d been cleaning and grinding an intake or exhaust valve the cost would have driven you to rid yourself of the car by now. I was being facetious. Sincere apologies for not being clear.
Ask hom exactly what he’s been cleaning. We’ll be able to give you a much better answer.
I also strongly suspect the EGR, especially since the “rattling” is probably pinging, but until the OP gets more information from the mechanic…
Thats got to be 4500 in clunker money as my 2004 F-150 books at less than 4500 in trade.
It has a laundry list of other little age related problems that make the c.a.r.s. deal look good now.