Can debris entering open exhaust port cause valve seat dr...

Q: Can debris entering open exhaust port cause valve seat dropping?

asked by on December 22, 2016

A mechanic did a routine exhaust manifold replacement on passenger side. On the first startup after this replacement he called me saying it made a loud clattering noise, and now it is misfiring badly on cylinder #4 which is the same passenger side. He had to drill two studs out that broke off to extract the bolts. Mechanic tried fixing issue by changing out parts to fix misfire but then did a test that diagnosed issue as valve seat failure.

Is it possible that debris entering the motor accidentally into an open exhaust port during the repair could set off a chain of events to cause a valve seat issue?

thanks Drew

My car has 115000 miles.
My car has an automatic transmission.

Hi Drew:

In most cases, when valve seat’s "drop" it’s caused by a reduction in lubrication or excessive heat built-up inside the cylinder heads. However, it’s possible for foreign debris to get stuck between the valve and the guides; which can lead to damage. However, without inspecting the cylinder head personally, it would be very irresponsible for us to determine whether or not the mechanics previous work caused this damage to occur. It’s more than likely that the valve seat was damaged prior.

Was this answer helpful?
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

oil leak thru transmission breather vent

There is no thermostat. To diagnose this, you should install a temperature gauge to determine what the operating temperature is. The A140E tends to run hot already and if the transmission is failing, heat generation could increase due to slipping...

How to set correct timing of cam gear to cam alignment.

Hi there. You will need to get a cam alignment gear or something that will hold the camshafts together. Then align up the camshafts to the correct alignment with both dots facing the two slots on the top of the...

No brakes

If the brake pedal is going to the floor even after replacing master cylinder and rear brakes you still have air in the brakes. You may need to use a pressure bleeder to push fluid through the system and bleed...

Related articles

A Buyer’s Guide to the 2012 Ford F-250
When When it comes to large, heavy-duty pickup trucks, the 2012 Ford F-250 only has two competitors – the Chevrolet Silverado HD and the Dodge Ram 2500/3500. Though the F-250 doesn’t outperform the Ram in the towing department, it certainly...
2011 Dodge Ram vs. 2011 Ford F-150: Which One Should I Buy?
Large trucks can be fun to drive, and even more fun to get dirty. Unfortunately, they may also cause you to get phone calls from friends who need to move into a new apartment. Fortunately, just having a truck may...
2012 Ford F-150 vs. 2012 Chevrolet Silverado: Which One Should I Buy?
When you’re ready to really get some work done, there’s nothing like a full size pickup truck. These trucks are ready to haul a big load and really get in there and get busy. SUVs are great for moving people,...