Pcv problem ?
Thread Starter
6th Gear
Joined: Jan 2019
Posts: 6
Likes: 0
Pcv problem ?
Hi guys, I have a newly acquired 89 c4, I'm just going through it finding and resolving all the small issues. I have noticed while driving what smells like oil fumes in the cabin, no problem when stationary. The pcv grommets are a bit loose (probably original) and need to be replaced but apart from that I can't see any obvious leaks or issues. Is there anything else I should check? Thanks in advance
Safety Car
Joined: May 2001
Posts: 4,720
Likes: 1,625
From: Fairfax Virginia
Welcome to the Corvette Forum! A First time user on the First day of 2019!!
The very first thing I would suggest is investing in a set of the Factory Service Manuals for your particular year Corvette. Please don't try the Chiltons, Clymers or any other aftermarket manuals, the Factory manual has more information about your Corvette. The manuals are available in print or on a DVD from FleaBay.
Since you bought the car have you changed the oil in it? Older motor oil has a habit of smelling nasty and permeating everything. If you are not certain of the oil's age just flush it with new oil. I flush it even if they claim it is brand new oil as I want to run the brand I use and I know when it was changed and when it will need it next time.
When I buy a car like a Corvette I go through all the systems and check and flush everything I can think of. That includes the Engine Oil, Power Steering Fluid, Brake Fluid, differential oil and replacing the auto trans filter and fluid as well (If automatic). I then put a new serpentine Belt and change the air filter and wiper blades. I just like starting at a point where everything has been serviced and I know when it was done. The brake fluid is frequently forgotten or ignored and then you have problems replacing the brake lines as they are steel and will rust away fairly quickly. On my ABS box in the back of the driver had one line change to appear as though it ate an olive in mid-line, water in the brake fluid is a constant problem.
When I bought my 1988 C4 I took my infrared thermometer and verified that all the half shaft joints were all running the same temperatures. If one was out of range then I would have both half shafts rebuilt with new Spicer U-Joints on all sides. Drive the care thru windy roads and listen for any unusual sounds or clicking to be sure that your Posi unit is okay. Again a flush with new Oil and the necessary Posi additive will make the rear of your car much happier. Using the same thermometer you can verify that all eight cylinders are firing and look for anything unusually hot (like Catalytic Converters that are partially blocked). You should see fairly consistent temperatures throughout the Car when checking with the thermometer.
You are wise to replace the PCV grommets and the PVC's themselves, so often people overlook these items. The hose itself might be the problem so try to change it all at one time. At this time I would start looking for ANY oil leaks, check the front and rear seals of the intake manifold as they like to leak. The front timing chain cover and the rear main seal are the other two prime offenders. I have found leaks on my C4 at the oil pressure sending units which can be solved easily. How many miles are on the engine in the Corvette? Does it have any modifications done to the car or its engine?
I am sure that others will add to the list of things to check and or replace but you should be on your way with what I started you off with, I hope that this helps you a bit!
Happy New Year and "Good Luck with your "New to You" Corvette!
CTMcCloskey
The very first thing I would suggest is investing in a set of the Factory Service Manuals for your particular year Corvette. Please don't try the Chiltons, Clymers or any other aftermarket manuals, the Factory manual has more information about your Corvette. The manuals are available in print or on a DVD from FleaBay.
Since you bought the car have you changed the oil in it? Older motor oil has a habit of smelling nasty and permeating everything. If you are not certain of the oil's age just flush it with new oil. I flush it even if they claim it is brand new oil as I want to run the brand I use and I know when it was changed and when it will need it next time.
When I buy a car like a Corvette I go through all the systems and check and flush everything I can think of. That includes the Engine Oil, Power Steering Fluid, Brake Fluid, differential oil and replacing the auto trans filter and fluid as well (If automatic). I then put a new serpentine Belt and change the air filter and wiper blades. I just like starting at a point where everything has been serviced and I know when it was done. The brake fluid is frequently forgotten or ignored and then you have problems replacing the brake lines as they are steel and will rust away fairly quickly. On my ABS box in the back of the driver had one line change to appear as though it ate an olive in mid-line, water in the brake fluid is a constant problem.
When I bought my 1988 C4 I took my infrared thermometer and verified that all the half shaft joints were all running the same temperatures. If one was out of range then I would have both half shafts rebuilt with new Spicer U-Joints on all sides. Drive the care thru windy roads and listen for any unusual sounds or clicking to be sure that your Posi unit is okay. Again a flush with new Oil and the necessary Posi additive will make the rear of your car much happier. Using the same thermometer you can verify that all eight cylinders are firing and look for anything unusually hot (like Catalytic Converters that are partially blocked). You should see fairly consistent temperatures throughout the Car when checking with the thermometer.
You are wise to replace the PCV grommets and the PVC's themselves, so often people overlook these items. The hose itself might be the problem so try to change it all at one time. At this time I would start looking for ANY oil leaks, check the front and rear seals of the intake manifold as they like to leak. The front timing chain cover and the rear main seal are the other two prime offenders. I have found leaks on my C4 at the oil pressure sending units which can be solved easily. How many miles are on the engine in the Corvette? Does it have any modifications done to the car or its engine?
I am sure that others will add to the list of things to check and or replace but you should be on your way with what I started you off with, I hope that this helps you a bit!
Happy New Year and "Good Luck with your "New to You" Corvette!
CTMcCloskey
Last edited by ctmccloskey; Jan 1, 2019 at 10:04 AM. Reason: Forgot the "Welcome to the Corvette Forum"
Thread Starter
6th Gear
Joined: Jan 2019
Posts: 6
Likes: 0
Welcome to the Corvette Forum! A First time user on the First day of 2019!!
The very first thing I would suggest is investing in a set of the Factory Service Manuals for your particular year Corvette. Please don't try the Chiltons, Clymers or any other aftermarket manuals, the Factory manual has more information about your Corvette. The manuals are available in print or on a DVD from FleaBay.
Since you bought the car have you changed the oil in it? Older motor oil has a habit of smelling nasty and permeating everything. If you are not certain of the oil's age just flush it with new oil. I flush it even if they claim it is brand new oil as I want to run the brand I use and I know when it was changed and when it will need it next time.
When I buy a car like a Corvette I go through all the systems and check and flush everything I can think of. That includes the Engine Oil, Power Steering Fluid, Brake Fluid, differential oil and replacing the auto trans filter and fluid as well (If automatic). I then put a new serpentine Belt and change the air filter and wiper blades. I just like starting at a point where everything has been serviced and I know when it was done. The brake fluid is frequently forgotten or ignored and then you have problems replacing the brake lines as they are steel and will rust away fairly quickly. On my ABS box in the back of the driver had one line change to appear as though it ate an olive in mid-line, water in the brake fluid is a constant problem.
When I bought my 1988 C4 I took my infrared thermometer and verified that all the half shaft joints were all running the same temperatures. If one was out of range then I would have both half shafts rebuilt with new Spicer U-Joints on all sides. Drive the care thru windy roads and listen for any unusual sounds or clicking to be sure that your Posi unit is okay. Again a flush with new Oil and the necessary Posi additive will make the rear of your car much happier. Using the same thermometer you can verify that all eight cylinders are firing and look for anything unusually hot (like Catalytic Converters that are partially blocked). You should see fairly consistent temperatures throughout the Car when checking with the thermometer.
You are wise to replace the PCV grommets and the PVC's themselves, so often people overlook these items. The hose itself might be the problem so try to change it all at one time. At this time I would start looking for ANY oil leaks, check the front and rear seals of the intake manifold as they like to leak. The front timing chain cover and the rear main seal are the other two prime offenders. I have found leaks on my C4 at the oil pressure sending units which can be solved easily. How many miles are on the engine in the Corvette? Does it have any modifications done to the car or its engine?
I am sure that others will add to the list of things to check and or replace but you should be on your way with what I started you off with, I hope that this helps you a bit!
Happy New Year and "Good Luck with your "New to You" Corvette!
CTMcCloskey
The very first thing I would suggest is investing in a set of the Factory Service Manuals for your particular year Corvette. Please don't try the Chiltons, Clymers or any other aftermarket manuals, the Factory manual has more information about your Corvette. The manuals are available in print or on a DVD from FleaBay.
Since you bought the car have you changed the oil in it? Older motor oil has a habit of smelling nasty and permeating everything. If you are not certain of the oil's age just flush it with new oil. I flush it even if they claim it is brand new oil as I want to run the brand I use and I know when it was changed and when it will need it next time.
When I buy a car like a Corvette I go through all the systems and check and flush everything I can think of. That includes the Engine Oil, Power Steering Fluid, Brake Fluid, differential oil and replacing the auto trans filter and fluid as well (If automatic). I then put a new serpentine Belt and change the air filter and wiper blades. I just like starting at a point where everything has been serviced and I know when it was done. The brake fluid is frequently forgotten or ignored and then you have problems replacing the brake lines as they are steel and will rust away fairly quickly. On my ABS box in the back of the driver had one line change to appear as though it ate an olive in mid-line, water in the brake fluid is a constant problem.
When I bought my 1988 C4 I took my infrared thermometer and verified that all the half shaft joints were all running the same temperatures. If one was out of range then I would have both half shafts rebuilt with new Spicer U-Joints on all sides. Drive the care thru windy roads and listen for any unusual sounds or clicking to be sure that your Posi unit is okay. Again a flush with new Oil and the necessary Posi additive will make the rear of your car much happier. Using the same thermometer you can verify that all eight cylinders are firing and look for anything unusually hot (like Catalytic Converters that are partially blocked). You should see fairly consistent temperatures throughout the Car when checking with the thermometer.
You are wise to replace the PCV grommets and the PVC's themselves, so often people overlook these items. The hose itself might be the problem so try to change it all at one time. At this time I would start looking for ANY oil leaks, check the front and rear seals of the intake manifold as they like to leak. The front timing chain cover and the rear main seal are the other two prime offenders. I have found leaks on my C4 at the oil pressure sending units which can be solved easily. How many miles are on the engine in the Corvette? Does it have any modifications done to the car or its engine?
I am sure that others will add to the list of things to check and or replace but you should be on your way with what I started you off with, I hope that this helps you a bit!
Happy New Year and "Good Luck with your "New to You" Corvette!
CTMcCloskey
thanks for the really detailed reply, the car has 110k with full service history and all receipts from new, it was serviced last in September 2018 with oil and filters done, running gear all seems too be fine with no worrying noises. As it's new to me I am giving it a once over and replacing all filters and fluids, however as I am in Ireland parts are not readily available so I am trying to put together an order from the US and am trying to cover as many bases as possible, pcv grommets are only a couple of bucks each but shipping is $18! I will check out some of the items you mentioned and let you know what shows up.
thanks again and happy New year
Oil Producer
Joined: Apr 2014
Posts: 9,349
Likes: 2,726
yeah, just read your first post and id say an oil leak that gets burnt off when running. forward movement brings the fumes into the ventinlet at base of windshield.
my 86 had the same thing it was both vc's leaking.
Team Owner
Joined: Jul 2004
Posts: 28,330
Likes: 3,245
From: Hartford WI
Welcome to the Corvette Forum! A First time user on the First day of 2019!!
The very first thing I would suggest is investing in a set of the Factory Service Manuals for your particular year Corvette. Please don't try the Chiltons, Clymers or any other aftermarket manuals, the Factory manual has more information about your Corvette. The manuals are available in print or on a DVD from FleaBay.
Since you bought the car have you changed the oil in it? Older motor oil has a habit of smelling nasty and permeating everything. If you are not certain of the oil's age just flush it with new oil. I flush it even if they claim it is brand new oil as I want to run the brand I use and I know when it was changed and when it will need it next time.
When I buy a car like a Corvette I go through all the systems and check and flush everything I can think of. That includes the Engine Oil, Power Steering Fluid, Brake Fluid, differential oil and replacing the auto trans filter and fluid as well (If automatic). I then put a new serpentine Belt and change the air filter and wiper blades. I just like starting at a point where everything has been serviced and I know when it was done. The brake fluid is frequently forgotten or ignored and then you have problems replacing the brake lines as they are steel and will rust away fairly quickly. On my ABS box in the back of the driver had one line change to appear as though it ate an olive in mid-line, water in the brake fluid is a constant problem.
When I bought my 1988 C4 I took my infrared thermometer and verified that all the half shaft joints were all running the same temperatures. If one was out of range then I would have both half shafts rebuilt with new Spicer U-Joints on all sides. Drive the care thru windy roads and listen for any unusual sounds or clicking to be sure that your Posi unit is okay. Again a flush with new Oil and the necessary Posi additive will make the rear of your car much happier. Using the same thermometer you can verify that all eight cylinders are firing and look for anything unusually hot (like Catalytic Converters that are partially blocked). You should see fairly consistent temperatures throughout the Car when checking with the thermometer.
You are wise to replace the PCV grommets and the PVC's themselves, so often people overlook these items. The hose itself might be the problem so try to change it all at one time. At this time I would start looking for ANY oil leaks, check the front and rear seals of the intake manifold as they like to leak. The front timing chain cover and the rear main seal are the other two prime offenders. I have found leaks on my C4 at the oil pressure sending units which can be solved easily. How many miles are on the engine in the Corvette? Does it have any modifications done to the car or its engine?
I am sure that others will add to the list of things to check and or replace but you should be on your way with what I started you off with, I hope that this helps you a bit!
Happy New Year and "Good Luck with your "New to You" Corvette!
CTMcCloskey
The very first thing I would suggest is investing in a set of the Factory Service Manuals for your particular year Corvette. Please don't try the Chiltons, Clymers or any other aftermarket manuals, the Factory manual has more information about your Corvette. The manuals are available in print or on a DVD from FleaBay.
Since you bought the car have you changed the oil in it? Older motor oil has a habit of smelling nasty and permeating everything. If you are not certain of the oil's age just flush it with new oil. I flush it even if they claim it is brand new oil as I want to run the brand I use and I know when it was changed and when it will need it next time.
When I buy a car like a Corvette I go through all the systems and check and flush everything I can think of. That includes the Engine Oil, Power Steering Fluid, Brake Fluid, differential oil and replacing the auto trans filter and fluid as well (If automatic). I then put a new serpentine Belt and change the air filter and wiper blades. I just like starting at a point where everything has been serviced and I know when it was done. The brake fluid is frequently forgotten or ignored and then you have problems replacing the brake lines as they are steel and will rust away fairly quickly. On my ABS box in the back of the driver had one line change to appear as though it ate an olive in mid-line, water in the brake fluid is a constant problem.
When I bought my 1988 C4 I took my infrared thermometer and verified that all the half shaft joints were all running the same temperatures. If one was out of range then I would have both half shafts rebuilt with new Spicer U-Joints on all sides. Drive the care thru windy roads and listen for any unusual sounds or clicking to be sure that your Posi unit is okay. Again a flush with new Oil and the necessary Posi additive will make the rear of your car much happier. Using the same thermometer you can verify that all eight cylinders are firing and look for anything unusually hot (like Catalytic Converters that are partially blocked). You should see fairly consistent temperatures throughout the Car when checking with the thermometer.
You are wise to replace the PCV grommets and the PVC's themselves, so often people overlook these items. The hose itself might be the problem so try to change it all at one time. At this time I would start looking for ANY oil leaks, check the front and rear seals of the intake manifold as they like to leak. The front timing chain cover and the rear main seal are the other two prime offenders. I have found leaks on my C4 at the oil pressure sending units which can be solved easily. How many miles are on the engine in the Corvette? Does it have any modifications done to the car or its engine?
I am sure that others will add to the list of things to check and or replace but you should be on your way with what I started you off with, I hope that this helps you a bit!
Happy New Year and "Good Luck with your "New to You" Corvette!
CTMcCloskey
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
2027 Corvette vs The World: Every Model vs Closest Competitor
Joe Kucinski
10 Most Common Corvette Problems of the Last 20 Years!
Joe Kucinski
5 MOST and 5 LEAST Popular Corvette Model Years in History!
Joe Kucinski
2027 Corvette Buyer's Guide: Everything You Need to Know!
Joe Kucinski
10 Things C8 Corvette Owners Hate (But Won't Tell You)
Joe Kucinski
10 Best Corvettes Coming to Barrett-Jackson Palm Beach 2026!
Brett Foote
Every Corvette Grand Sport Explained! (C2, C4, C6, C7, & C8)
Joe Kucinski
Grand Sport & Grand Sport X Launch Alongside All-New 535hp LS6 V8!
Michael S. Palmer