Intake manifold bolts loosen after lower gasket change? - Ranger-Forums - The Ultimate Ford Ranger Resource


4.0L OHV & SOHC V6 Tech General discussion of 4.0L OHV and SOHC V6 Ford Ranger engines.

Reply
 
LinkBack Thread Tools Search this Thread
  #1  
Old 09-25-2014
BL00DPIG's Avatar
Member
Thread Starter
 
Join Date: Mar 2014
Location: Ayden
Posts: 30
Icon5 Intake manifold bolts loosen after lower gasket change?

97' ranger 4.0: About a month ago I noticed that my Ranger exhaust had the unmistakable "sweet" smell of coolant. I replaced the the the lower intake manifold gasket with original OEM gasket as it was pulling codes P0171 and P0174. I reset the ECU. All seemed fine, until yesterday. Engine light back on and same codes pull up. Just wondering, Do the intake manifold bolts loosen over time (after pulling intake manifold) and I just need to re-torque them or is there a bigger issue?

Last edited by BL00DPIG; 09-25-2014 at 05:24 AM.
Reply With Quote
  #2  
Old 09-25-2014
RF Veteran
iTrader: (1)
 
Join Date: Jan 2014
Location: Vancouver, BC
Posts: 7,601
It is unusual to get coolant into the exhaust via an intake manifold leak, not unheard of just not usual.
Usual with 4.0l is a cracked head from past over heating or a bad head gasket.

Most common reason for 171 and 174 at the same time is a dirty MAF(mass air flow) sensor.
MAF sensor tells computer the amount of air coming into the engine and the computer bases the fuel needed on that data.
After the fuel is burned the O2 sensors tell the computer if mix is lean or rich.
If the air flow data and the O2 data don't add up to the computers calculations of the amount of fuel that should be being used, you get a code.

Since you are getting codes for both banks/sides of the engine the common denominator is the MAF sensor, or computer itself.
If it was a lower intake leak, then only one bank would be effected, if it was a failing O2 sensor it would only have 1 code.

An upper intake vacuum leak can also cause the dual codes, to test for vacuum leak, warm up engine and let it idle, should be about 700-800 RPM, now unplug IAC Valve wires, idle should drop to 500 RPMs or engine may even stall, either is OK, it means there is no vacuum leak.
If idle stays high then there is a vacuum leak.

On the 4.0l the MAF is at the air cleaner and has an air plenum(tube) that goes to the upper intake, if that air plenum has a leak then it would have the same effect as a dirty MAF sensor, not all the air coming in is passing thru the MAF sensor.
The PCV(positive crankcase ventilation) system is part of this, the oil filler cap and dipstick seal the crankcase and valve covers.
The PCV Valve pulls air out and the vent hose(from oil filler tube to air plenum) allows "metered" air to come in.
Often if you unscrew the oil filler cap while engine is running engine may stall or idle will go high, you created a vacuum leak.

Last edited by RonD; 09-25-2014 at 10:12 AM.
Reply With Quote
  #3  
Old 09-27-2014
BL00DPIG's Avatar
Member
Thread Starter
 
Join Date: Mar 2014
Location: Ayden
Posts: 30
[QUOTE=RonD;2076416]

Most common reason for 171 and 174 at the same time is a dirty MAF(mass air flow) sensor.
MAF sensor tells computer the amount of air coming into the engine and the computer bases the fuel needed on that data.
You were correct about the MAF sensor. I bought a can of MAF Cleaner, cleaned and truck runs better, still has a miss due to the leaking head gasket.
Also, the intake bolts did loosen drastically, torqued them to 25-ft lbs the first go round then 59 ft lbs the second round when I replaced the lower intake manifold gasket. After checking them this time most of them were below 40 ft lbs. Thanks for your info RonD, but I have one more question. I noticed when ordering the head gasket set, some of them are marked "Set X" is this what I need for a 4.0?
Reply With Quote
  #4  
Old 09-27-2014
RF Veteran
iTrader: (1)
 
Join Date: Jan 2014
Location: Vancouver, BC
Posts: 7,601
The "X" is from the 8th digit in the VIN number for engine type
X = 4.0l OHV (1990-2000 Rangers)
E = 4.0l SOHC (2001 and up Rangers)

You want the "X"
Reply With Quote
  #5  
Old 09-28-2014
BL00DPIG's Avatar
Member
Thread Starter
 
Join Date: Mar 2014
Location: Ayden
Posts: 30
Quote:
Originally Posted by RonD View Post
The "X" is from the 8th digit in the VIN number for engine type
X = 4.0l OHV (1990-2000 Rangers)
E = 4.0l SOHC (2001 and up Rangers)

You want the "X"
Are you a Ford Master Mech RonD? Every response you have on the few issues I have posted have been very helpful. You should write your own repair manuals..." Repair Manual for Dummies"
Reply With Quote
  #6  
Old 09-28-2014
RF Veteran
iTrader: (1)
 
Join Date: Jan 2014
Location: Vancouver, BC
Posts: 7,601
lol, thank you.

They say you learn more from your mistakes than from your success's.

I have made alot of mistakes..................and still learning
Reply With Quote
  #7  
Old 10-06-2014
BL00DPIG's Avatar
Member
Thread Starter
 
Join Date: Mar 2014
Location: Ayden
Posts: 30
Well I pulled the head and the gasket was in pieces. #3 cylinder definitely had signs of coolant entering the cylinder. Fixed.
Reply With Quote
  #8  
Old 10-06-2014
RF Veteran
iTrader: (1)
 
Join Date: Jan 2014
Location: Vancouver, BC
Posts: 7,601
Good work
Reply With Quote
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
Intake manifold lower gasket.. : / TexasEdge 2.9L & 3.0L V6 Tech 9 06-13-2015 11:34 PM
Rough Shifting after intake manifold gasket replacement apnubern 4.0L OHV & SOHC V6 Tech 3 04-19-2012 10:42 AM
Lower Intake Manifold Gasket Replacement jbmcquade General Ford Ranger Discussion 3 04-17-2011 03:44 PM
Intake Manifold Gasket/Intake Manifold fordboston 4.0L OHV & SOHC V6 Tech 6 01-25-2010 10:37 PM
Intake Manifold Gasket Install - Use RTV too? R Carson 2.9L & 3.0L V6 Tech 3 04-01-2009 06:44 PM


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -6. The time now is 09:24 AM.


We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.