Valve Stem (heads) Issue?

I was driving today and a buddy was following behind me...when we got to our destination he told me he thought my valve stem seals might need to be changed b/c I was blowing some smoke on hard accelerations (FYI - I can smell burnt oil after high RPM pulls).

Does his suggestion make sense? Is this something I should definitely get checked out?

I'm about to have the IMRCs cleaned or deleted, so I'm guessing both jobs would need to be done at the same time.

I called a different buddy who is a mechanic and he said to sell the car b/c it's all down hill from here....Is he correct?

I'm not very familiar with all this but some people are telling me I "might as well port the heads/intake while they are out" and "might as well do a full C swap"...

How big of a deal is all this? Is this like major money just to replace the valve stem seals?

Valve stem seal replacement is a fairly complex procedure, and usually requires specialized tools to complete. You've got to pull the valve spring off of the valve, and then remove and replace the seal. Depending on the shop you take it to, the estimate might be fairly high. I've replaced the seals on an OHV engine before, but that's fairly simple compared to the DOHC's architecture. I guess what I'm trying to say is that I've always heard valve stem seals were a bit of an issue for these cars when they get older. I mean, my Cobra smokes on startup every once in a while and will blow a cloud of smoke on the first real wide open pull I do after I park it, but it isn't really a death sentence. I definitely wouldn't get rid of the car due to some leaky valve stem seals.

It would be a good time to do a C head swap. Honestly, unless it's really bad keep driving it and save up.

Sent from my [device_name] using the svtperformance.com mobile app

No smoke during cold start or partial throttle when i moved the car in the driveway this am...does this mean it's not the valve seals? Or maybe that the seals just have yet to fully deteriorate?

Do you have an oil separator? When you take the IMRCs off, you'll probably see a big pool of oil in the lower intake that entered through the PCV line. I know that's what I found when I deleted mine. Usually the trademark sign of valve stem seals is blue smoke on startup, since the oil leaks down and collects on the tops of the pistons. I know mine will cough out a cloud of smoke if it sits more than 24 hours.

just bought a separator and a new pcv valve...hopefully can install them this weekend.

If you have the ambition and a weekend, with the purchase of a special valve spring compressor (like this one for example: https://www.ebay.com/i/192233713082?chn=ps) and some parts from a leak down tester (which can typically be borrowed for free from an auto parts store), valve stem seals can be done with the heads on the engine, in the car.

Don't let people talk you into ripping an engine out/apart, spending thousand on repairs or new heads when it's not needed.

Valve stem seals usually manifest as puffs of smoke on startup, not at high rpm. High rpm sounds like a ring seal or tune issue. If your tune is on point, get a compression and leak down test before you tear into the motor.

Tabres said:

Don't let people talk you into ripping an engine out/apart, spending thousand on repairs or new heads when it's not needed.

Click to expand...

EXACTLY! What you should do depends on YOUR expectations for the car.

98SVTContour98 said:

I called a different buddy who is a mechanic and he said to sell the car b/c it's all down hill from here....Is he correct?

Click to expand...

Get a different buddy. This is complete nonsense. Yes -your car is 20ish years old and will take some effort to maintain. Does that really matter when you are driving down the road with a smile on your face? Any fool with a checkbook can buy a car. I have a lot more respect for a person that takes the effort to keep one on the road.

omj said:

get a compression and leak down test before you tear into the motor.

Click to expand...

This is great advice - engine trouble shooting 101.

Start simple. Your thought to clean the IMRCs is right on point. Take the butterfly shafts out and you will notice dried up o-rings on both ends. Replacing them will stop a major vacuum leak for about $1.00. If you have not cleaned the injectors or replaced the fuel filter, get those things done. Check for cracked vacuum lines and replace any that are suspect. Button it all up and I bet your engine will feel totally different.

omj said:

Valve stem seals usually manifest as puffs of smoke on startup, not at high rpm. High rpm sounds like a valve stem or tune issue. If your tune is on point, get a compression and leak down test before you tear into the motor.

Click to expand...

Valve stem seals are usually a cold start puff. I've always been under the impression oil smoke on hard acceleration is ring wear. Now, if it's black smoke, which would indicate a rich condition, valve stem seals and ring wear aren't at all what you need to start looking at.

ForcFed93 said:

Valve stem seals are usually a cold start puff. I've always been under the impression oil smoke on hard acceleration is ring wear. Now, if it's black smoke, which would indicate a rich condition, valve stem seals and ring wear aren't at all what you need to start looking at.

Click to expand...

You are right. I went in an edited my post to say "ring seal" instead of "valve stem." My mind started to wonder mid sentence and then got back on track at the end. My bad.

Where are the ring seals located?

FYI - I installed the catch can and new PCV Valve...Did light driving only since the weekend install and did not have any oil in the catch can...well last night I decided to hit it hard in different gears just to double check my IMRC issue...I still think I'm having the IMRC issue but another thing of note was that I was not getting the burnt oil smell anymore and when I got home I checked the catch can and it had oil in it!

98SVTContour98 said:

Where are the ring seals located?

Click to expand...

Rings, are your piston rings. When they're worn, you're in for a rebuild. Excessive oil in your catch can will further reinforce this. If your rings are worn, you'll have more blow-by which will induce pressure into your crank case.

I'd do a leak down test to assess the health of your engine. Realistically, you could drive with rings that are going out for quite a long while as you save for a rebuild. You're not really risking a catastrophic failure like with a bearing failure.

ForcFed93 said:

Rings, are your piston rings. When they're worn, you're in for a rebuild. Excessive oil in your catch can will further reinforce this. If your rings are worn, you'll have more blow-by which will induce pressure into your crank case.

I'd do a leak down test to assess the health of your engine. Realistically, you could drive with rings that are going out for quite a long while as you save for a rebuild. You're not really risking a catastrophic failure like with a bearing failure.

Click to expand...

is "leak down test" the same as a "compression test"?

98SVTContour98 said:

is "leak down test" the same as a "compression test"?

Click to expand...

No, they are two separate tests.

A compression test is done by hooking a gauge up to a cylinder through the spark plug hole, cranking the engine over and measuring how much pressure the engine builds in that cylinder. You want to do it for all cylinders. The reading can tell you several things. You're looking for consistent values across all cylinders. Low readings in one specific cylinder might indicate a bad valve. Low readings in two adjacent cylinders normally suggests a head gasket issue. Low compression in several cylinders would indicate worn piston rings.

A leak down test, instead of measuring how much pressure the engine makes like during a compression test, measures an engine's ability to hold pressure. With a special spark plug fitting, while the cylinder is at TDC, you introduce compressed air into the cylinder. Normally when there are issues you'll hear the air escaping somewhere. Out of the intake manifold/throttle body would indicate a bad intake valve. Air out of the exhaust pipe/manifold is obviously a bad exhaust valve. Out of the PCV or areas like the oil filler cap is normally piston rings. Air bubbles in the coolant typically is a bad head gasket or cracked cylinder head.

Try some red devil stop oil leak. Worked on one of my mustangs years ago. Fixing to add some to my son's 04 gt with leaky valve stem seals

Sent from my [device_name] using the svtperformance.com mobile app

compression test results

175
167
162
?
155
167
150
152

The question mark is one we haven't been able to get the plug out for...so trying again this am on that one. From what I've read on SVTP, as long as all values are within 75% of the highest value, then Ford considers that spec....but i'd really love to know what Ford considers ideal or proper values.

96GT226410 said:

It would be a good time to do a C head swap. Honestly, unless it's really bad keep driving it and save up.

Sent from my [device_name] using the svtperformance.com mobile app

Click to expand...

What's the overall cost of a C-Swap (parts and labor)? Keep in mind I can't do any of the work myself.

98SVTContour98 said:

What's the overall cost of a C-Swap (parts and labor)? Keep in mind I can't do any of the work myself.

Click to expand...

Two options:

C heads with matching intake manifold and throttle and cruise cables.

C heads with C head lower and adapter for the B head upper and thus retaining your throttle and cruise cables.


As far as labor, it should be the same as head gaskets so I guess you're looking at around $1,000 give or take. If you're unable to do it yourself it's not really worth it.

Sent from my SM-G935V using the svtperformance.com mobile app