Hey everyone. I've got a 99' Tahoe with the 5.7 vortec. The truck has 127,000 miles and is lucky to see 1,000 miles a year these days. Overall, it is in good mechanical shape, but obviously does suffer some from the lack of use. Years ago, when the truck was maybe 3 years old, we had a major hail storm and I had the hood replaced as it was covered by insurance. I had a steel cowl hood put on. I have put maybe 40k miles on the truck since the hood was installed overall, and I have replaced at least 3 distributor caps/rotors because it will start to miss. The inside of the actual distributor looks rusty, and I just don't think this is right. I am starting to think that maybe it is due to the open cowl on this hood and am starting to wonder if I should just go back to a stock hood to help keep the rain water to a minimum. Have any of you had issues with cowl hoods and moisture issues with your distributors? I like the look of the hood, but I'm more concerned(I'm getting older) about dependability and longevity. Does anyone have any words to share about cowl hood problems? I have also learned that I have poor luck with distributor caps other than AC Delco and crossfiring issues. Can anyone else attest to this?
Distributor corrosion questions...
- Thread starter bptahoe
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drakon543
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does your cowl have the rear lip or is it fully raised in the back so there's no possibility of sealing the back edge. with the stock hoods losing the weather stripping on the back edge above the firewall can cause this. some cowl hoods ive seen leave a lip just below the cowl to allow the seal to still do its job and keep water from going straight down ontop of the distributor. also the distributor caps are known to crack so you should also check that as it will allow for excessive moisture build up. lastly have you ever had the distributor replaced on the truck or is it still the original. most aftermarket distributors are well known to have moisture problems on the 5.7 and the best options are an oem acdelco or i think the davis unit was also popular.
Hello drakon543 ... thanks for joining in. This cowl hood is completely open in the rear, and I never would have suspected any concerns way back when I bought it. I guess you'd say it's a 'real' cowl even though it only for looks for me. I didn't buy this Tahoe new. It had around 59k on it when I got it, so it likely had the factory distributor in it, but I cannot confirm this. I haven't replaced it but have been thinking about it due to the rust I saw last time I replaced the cap. I put a cap on about 3 years ago, due to a miss(which it fixed but I now have it again), but the cap only has maybe 2k miles on it. It seems like last time I had to use screws with nuts on the underside of the distributor because they wouldn't tighten. The distributor 'head' is plastic, isn't it? I don't know if a cap is what I need this time, but if I was a betting man......
I don't think the cowl has anything to do with the problem. I think that it sits too much does. The system is going to get moisture in it just because of moisture in the air and if I remember there is a screened vent in the bottom shelf of the distributor. The opening would have to have direct feed of water to get down in there thru that cowl. I may be wrong but I feel that the problem is inactivity. After all, you don't have water directly coming down brake rotors and they rust if not driven. Maybe I am misunderstanding the concern but that is my take on it. You said yourself, 1000 miles a year is not enough.
By the way, congrats on finally posting in the forum.
By the way, congrats on finally posting in the forum.
drakon543
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as far as the various distributor caps its been mentioned across the web about aftermarket distributor caps not sealing well enough and causes your problems. im no guru on the subject but i self inflicted myself alot of problems when i had my 97. cheap parts miss matched parts and assuming expensive performance versions would work better or as good vs oem or cheap parts. @PNW VietVet its not specifically the water going directly into the distributor its the excessive build up of water and moisture around the distributor thats counteracting the purpose of the vent. there's people who knock the screen completely out for extra venting and people who actually drill extra holes in the base for more venting. in no way am i suggesting you do that as i think its stupid and the real problem should be addressed. anyway as PNW VietVet stated sitting alot can play a factor here. if you dont periodically run the truck moisture will get in there and sit and without the heat evaporating from running the engine. if the truck is left to sit outside for long periods of time without being run at all there's not going to be much you can do about it besides making sure you have an extra cap and rotor available. i suggest getting a habit of making sure the truck is run once a month atleast. if you decide to replace the distributor look at the 2 options i suggested and make sure you make a note for yourself. ac delco distributor with a cheap cap can possibly bring your issue back to where it was. so acdelco distributor with acdelco cap and rotor or the davis dizzy with the davis cap and rotor.
again im no guru on this subject so dont get all your information just here i just happened to fight the same issue for several years because i was stubborn and cheap or well broke a few times.
again im no guru on this subject so dont get all your information just here i just happened to fight the same issue for several years because i was stubborn and cheap or well broke a few times.
I'm in agreement with Drakon and PnwVietvet- Time/mileage/enviroment. Also the clogged/corroded vent screen makes it worse. Condensation is the cause, day to nite or hot to cold. I have been spraying my internals carefully with LPS2 which seems to help here as its is hi humidity salt air. The caps I use are AC Delco or United DCR-820X only.
Long term maintenence shows no matter what 2-3 years is max on the cap, with reduced life of all other components if run too long. When gas mileage begins to slip it's time. No codes till obvious failure. Currently running United distributors with good results. 20k-60k mileage per cap. Any Ign issues ALWAYS change cap. I really like these motors for maint. Just a learning curve to find what works longer term.
At your mileage, cap/ rotor/ wires/ plugs/ filters. Carry spare coil, spare ICM. Delco only. Use NGK plugs, Packard wires.
Good luck and let us know how it's working to increase the total knowns.
Long term maintenence shows no matter what 2-3 years is max on the cap, with reduced life of all other components if run too long. When gas mileage begins to slip it's time. No codes till obvious failure. Currently running United distributors with good results. 20k-60k mileage per cap. Any Ign issues ALWAYS change cap. I really like these motors for maint. Just a learning curve to find what works longer term.
At your mileage, cap/ rotor/ wires/ plugs/ filters. Carry spare coil, spare ICM. Delco only. Use NGK plugs, Packard wires.
Good luck and let us know how it's working to increase the total knowns.
Hello PNW VietNet! Thanks for the info! You made a good point. Last time I replaced the cap and button, I was just really surprised and concerned by the rust in the distributor. I have never had the distributor out, but I have read about the vent that is supposed to be in the assembly somewhere. I don't have the garage space to be able to keep this thing in 'the dry', so it is at the mercy of the elements. My first thoughts were direct water being administered somehow, but I'm sure it could just be residual moisture and the lack of use. The last time I put a cap on, I coated everything lightly with WD40(it's all I had), but you know what I was attempting.
Drakon543, I don't guess I always think that the OEM parts are the end all be all, but I think they are often better than some of the low quality aftermarkets. I'm not usually afraid to try some of the aftermarket items, since many of them are made by the same manufacturers anyway, but it really bit me on this truck years ago. When I put the first new-to-me cap and rotor on((years and years ago)), the truck ran well for a couple of months and then got harder and harder to start. It got to the point where it would not start, but I had no CELs, and no clues. I threw parts at it and was at a loss for months and months until an old Chevy guy told me to put an ACDelco cap on it, and sure enough, it started right up. I'm probably going to do plugs, wires, cap and rotor all together this time and I need to start driving it to work at least once every 2 weeks. I don't want to replaced the dizzy unless I see that I need to. I'm going to research the Davis items. I don't mind buying and paying for the good stuff, but sometimes you don't know which stuff is the good stuff until the other stuff lets you down...haha. I truly appreciate the information and suggestions. They are always welcome here.
Exp500, hello! I know the drive intervals are a problem. I have got to do better on that. I have so many cars, old used ones, that I always jump in one of the little economisers to go to work in.
I am glad to hear that my short dizzy cap lifespan is not totally uncommon. I know the one that is on the truck now can't have 3k miles on it, but it has been on several years. It is an ACDelco though. Now, I don't know for sure that the cap is the problem this time, but the truck is missing at idle and particularly under load. One day it wasn't and then one day it was.
Is it worth buying larger diameter plug wires for a stock truck? I am not familiar with Packard wires, so I'll look into them.
bptahoe- The Packard wires are a step down from Delco, Same wire with different boots. Packard was the OEM MFR, don't know if they still are. About 1/2 price of Delco and last. I have installed many of the crab distributors from United and like them, But you MUST only use DCR820X cap, others blow out from coil terminal inside. If you change dist you will likely REQUIRE a scanner to set timing. Many cheap bluetooths work to set cam angle offset or you set a P-1351 code. BAFX is one about $20.
I've also run into chineese AC plugs that didn't last, Recommend NGK now.
I keep a couple fleets of this vintage alive now as work trucks, a few at 300k miles+. So what works is most important.
Get a fuel pressure gauge with a hose long enough to reach the windshield, A spark tester, Multimeter And Scanner then you can do 95 percent of the items yourself. RockAuto is your friend! Good Luck.
I've also run into chineese AC plugs that didn't last, Recommend NGK now.
I keep a couple fleets of this vintage alive now as work trucks, a few at 300k miles+. So what works is most important.
Get a fuel pressure gauge with a hose long enough to reach the windshield, A spark tester, Multimeter And Scanner then you can do 95 percent of the items yourself. RockAuto is your friend! Good Luck.
