Ford F-150 - 1997-2003 :: 1998 - Air From Defrost Only - Vacuum Leak?
Jan 8, 2017
This has been on going for the past year. The blend works fine. Fan speed works correctly. The selection for ac, max ac, etc., will only allow air through defrost vents. Vacuum leak?
1998 4.6 auto super cab
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I know all about vacuum leaks and such causing this problem, and I tend to think that is my problem. But isn't the temp change dial also vacuum controlled (in my case of an 06 f250 6.0) by that valve near the oil fill tube on the passenger side? I ask because, while I am stuck on defrost i can change the temp of the air that comes out still, telling me there is enough vacuum in the system to at least control that.
I also know everyone talks about checking the ESOF system for cracked lines/leaks, but this shouldn't come in to play unless I have 4WD selected or if the EFOF solenoid is bad, right? I just got done tearing the top end of this engine apart, twice, for oil temp problems and am about done working on this POS!!!
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Ok, I have capped off the vacuum lines to the front hubs and replaced the vacuum solenoid on the passenger inner fender. Still stuck on defrost. I know there are several options from this point what would be the next step after what I have just recently done. Going away on a ski trip and would like to have it working properly before I go.
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I have a 2004 Ford Escape 3.0 V6 FWD, and the air conditioning has been blowing only to defrost for a few weeks now. After many searches online, most sources seem to agree it is a vacuum leak, as the selector switch is vacuum driven if you want anything except defrost. I popped the hood and within one minute I found one open vacuum line that looks like it has been worn in two.
The line in question goes from the vacuum canister towards the passenger side of the firewall, then goes to a T connector, then a line (the one that is broken) continues towards the heater core lines to where the break in the line is. I found a picture online of what it should look like, but I am having trouble accessing the line that goes through the firewall and behind the glove compartment. I am pretty sure this vacuum line continues through the firewall between the two heater lines, but after that I am stumped.
I popped the glove box down out of the way and I see two thin vacuum lines and a small metal "can" nearby. The black line goes from a fitting and into the A/C bundle, and the white line goes from the top of the metal canister and down into the same bundle. My main question is which line controls the AC selector, and how do I pass a replacement line through that part of the firewall to make a good connection, as it seems the break is at the firewall itself with no extra sticking out for me to connect to.
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1998 F150 XLT 4.6l automatic,,,
Drove the truck on a trip the other day, about 650 miles with a loaded 5x8 trailer in tow. A/C started acting weird. When the truck was on level ground, or going down hill, the A/C was fine. Cold air coming out the correct dash vents. As soon as I started up hill, or put the truck under strain of acceleration, the A/C would stop blowing out the dash vents and would start coming out the floor or defrost vents, or just not come out anywhere.
When I turned the A/C off and just used the vent setting, it would do the same thing with the fresh air. I guessing this has something to do with my vacuum lines, somewhere. What I should be looking for and where?
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I noticed a vacuum line hanging under my 98 F 150 4x4 I traced it out to my front axle question is where does the other end go I have looked but no luck to where it goes.
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It has been since the 80's that I have attempted to do any work on a vehicle. How do I find a vacuum leak and where is my vacuum canister. I am assuming that it is a vacuum leak for anytime my engine has a load on it the air stops coming out of the dash vents and goes to the defrost vents. I have an 2000 F150 with the large engine with about 112,000 miles.
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Ok, I know I have a vaccum leak. I have manual hubs now and those lines are capped. The AC is blowing through the deforst and the pump is running non stop. I have replaced the vac pump a couple of years ago and it worked fine then. any other places to look?
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I had my fuel system cleaned by the dealership last weekend and I feel like I gained 50hp+ ... Now its throwing a P0171 about a week and a half later. My computer also listed P0174 under the pending codes or whatever the section was.
2003 F150 5.4L ... I cleaned the MAF sensor a couple weeks back which stopped a rough idle and I have put some 300+ miles on it since. about 200 miles since the fuel system cleaning.
I got home and popped the hood and it sounded like a vacuum cleaner. Guess it is a vacuum leak. I might need to stop using this ford house. I swear this is the second time there was a vacuum leak(I think, first time they said it was spark gap issue). I'll be heading back in the morning now.
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I'm getting the p1131 error on my 2000 xlt f150 5.4l. I know it's usually a vacuum leak on the pcv hosing, which I did have at the back and replaced as well as other softer joining sections(3 to be exact lol), but I'm still getting this error. Changed out my plugs and cops(as they needed it) and the back two plugs on both bank 1 and 2(plugs 4&8) were both white! Since this is an obvious indication of a lean burning cylinder can I make the assumption my most likely problem is dirty fuel injectors on those cylinders?
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I've had this problem for a little while now, my 97' F150 V8 4.6L, has been running real loud and heavy. When it starts up it sounds like a race car. It finally shot me a code for P0171 - Bank 1 (passenger side) running too lean. From what I've read, this is most likely a vacuum leak but I don't know too much about it.
A couple of things I've noticed while driving it around:
1. If you are in the engine compartment while its running, you smell the excess gas on the passenger side of the truck.
2. The exhaust also smells really heavy
3. The loud and heavy running is mainly when accelerating, if I maintain a constant speed at for a little while it almost starts to run normal. Cruising down the highway its almost just as quiet as before the issue
4. Engine coolant heats up much more quickly, but doesn't get above operating temperature (read from tuner, never above 200 degrees)
In response to the problem I replaced both the O2 sensors closest to the engine and the PCV and elbow. No change. Have a fuel filter ready to install, but for some reason I don't think that is it either, as it would probably effect both bank 1 and 2.
Like I said I'm not too well versed in the vacuum system but if any of these symptoms stand out I'd love to hear your thoughts.
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I am having problems with a 2003 Ford F 150 with a 4.2 L V6. The problem is that it is giving me code errors that would indicate bad O2 sensors. I replaced both the upper and lower O2 sensors, and still I get the same codes. I was told by the mechanic with the computer reader that this usually means a bad vacuum seal. He suggested looking for bad hoses, but did not offer much more than that. How to proceed?
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So.... here's my issue. I have a 2001 supercrew 5.4 and runs great all day long, no problem starting or anything. After I have driven it for a while and turn the AC on it cools off very good then after about a 1/2hr. the truck tries to stall. It almost sounds like a vacuum leak and really bogs down. I can wait about 2hrs and then with the AC off the truck starts and drives like it should. I am steering to the IAC valve but would like to know if this is it.
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Recently I have been having a strong gas smell coming from my 1997 F150 Supercab 4.6L 2wd. It is not happening all of the time. I have also been hearing what sounds like a vacuum line leak. A loud shrill which varies with the engine rpm. This also does not happen all of the time.
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I am in the process of trying to chase down a vacuum leak on my 2003 F150 with the 5.4. I have checked all lines and cannot find it. I decided to check the long term fuel trim and noticed that my bank 1 is slightly higher than bank 2 (screenshot attached). Is this enough to assume the leak is on the bank 1 side?
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My heater core has a leak in it, but I can not get it replaced so I want to bypass it. How do I do that? Is there a video somewhere? Or tutorial with pictures? F-150 1998 ....
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1998 F150 4x4 4.2 ... Small leak spraying out of a steel pipe onto the front of the motor. This isn't my truck so I'm not very familiar with it but looks like there is a pipe that come from the water pump threw a bracket and y's and one end has a hose going to heater core n the other part is where the leak is I think it has a hose connected to it that goes to the intake. Only leaks when thermostat open. I'm going to take it apart tonight n see what I find. Iv looked for a replacement part and found nothing so I am going to try n replace the steel pipe with hose.
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I have a 1998 f150 xlt, supercab, 4x4, 4.6 Romeo (truck production date is 12/97). And I have a oil leak.
Its on the drivers side of the engine. There is a nipple on the head, next to the firewall, directly above where the exhaust pipe and exhaust manifold meet. It looks to have some sort of bolt/flush stud inside the nipple. I have oil seeping by the bolt/stud and leaking onto my exhaust pipe. its a constant but slow drip.
What this is or how to fix it? Is this a common problem? I can take a pic but cant find my camera at the moment.
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New truck to me. Truck was advertised with a slow coolant leak. Figured I would trace the leak down and get it repaired no issues. Anyway, working on it this evening I take a close look around the oil filler area and notice the dreaded milkshake color.
I drained the oil out of the truck and the oil actually came out nice and black. Is the headgasket the only area that would cause the oil/coolant mixture? Supposedly the truck has never been overheated.
At any rate, on to find articles on how to pull apart a 4.6L Triton head. I'll see if I'm up to this challenge.
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I have a 2003 Explorer with the 4.0 K motor. It has a vacuum leak and the check engine light will come on from time to time. My work buddy has a high end computer and it showed that the driver side bank was running lean. The computer showed the O2 sensors to be working fine, and I replaced the PCV valve. All other vacuum line appear to be in good condition and I tried the spray test with the break cleaner with the motor running. This is leading me to believe the air intake gaskets where due for replacement. Here is my problem, I can not get the last bolt out of the plenum. The one on the driver side up against the fire wall. I tried to remove the cowl in order to get a straight shot at it but I can not get the seem seal to break free.
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In the past, I've had the common issues of vacuum leaks causing issues as evident from the defrost/ac and then finding busted vacuum lines. Changed out and everything fine for a few years. Now, i dont have 4wd but i dont have the tell tale vacuum leak signs. Also, even if i manually engage the hubs, still no 4wd.
I try to listen for the transfer case to engage when i switch from 2wd to 4wd, I think I hear it engaging, but to be honest the 7.3 makes so much racket Im not positive that Im hearing it, or at least not hearing it the way I "think" that i heard it in the past. I seem to recall a distinctive clunk when engaging, now its barely audible if at all. Now when I switch to 4-Low, there is the distinctive sound, and it does goes into low drive, just that its only 2wd-low, still no front wheel action.
I have never had any issues before other than the vacuum leaks, have never had reason to dig into the transfer case for any reason. The only time it has ever been touched was last summer when i had the BTS installed and all they did was remove and replace.
Do I finally need to either rebuild or replace my hubs? Is it possible not to have 4wd even with hubs manually engaged? Or is there an issue with the t-case? Or is there something else going on? I have access to a lift to attempt "driving" while all wheels off the ground, its just not mine and its a tight fit and a pain to get my truck on it.
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