Gas tank question

[JMRide76]

Hey guys,

Just bought a 69 k10 swb a few weeks ago and trying to get it running. It had a locking gas cap on it and the previous owner had lost the key. I got the cap off and I have bought two caps from local parts stores and they were both too big and would not fit.

I was checking out the LMC catalog and I found that there are tanks with and without vent hoses(evaporative emission control). Mine has a vent hose. But according to their catalog, those tanks are only on 70-71 trucks.

This truck is not original and I don't have a lot of information on its past. I do know it was partially restored when the previous owner bought it. Is it likely that whoever did the previous restoration put a 70-71 cab on a 69 frame? Is there anyway I can confirm this? The front end is a 69-70 front end. The plate with the VIN number is not mounted to the cab, it is laying in the glove box.

Also, is the fuel cap smaller on the tanks with the vent hoses? Thanks for any help.

John

[Keller]

Im not sure why you're having trouble with the gas caps... last I looked at LMC I thought that both tanks they sell have 2" inlet tubes so wouldn't they have the same caps? Anyways, I was going to post a similar thread... did you clean your tank? I just bought a '72 Cheyenne Super that sat for about 2 years and went to drain the tank last weekend and it was dry. Would I be alright putting new gas in the tank without cleaning it? I don't have the resources to clean the tank myself (no way to dispose of the chemicals safely) and I could buy a new tank for what a local shop would charge me to clean the old one. I am on a budget and didn't have the extra $200 for a new tank in my budget.

[mbgmike]

Originally Posted by JMRide76

Hey guys,

Just bought a 69 k10 swb a few weeks ago and trying to get it running. It had a locking gas cap on it and the previous owner had lost the key. I got the cap off and I have bought two caps from local parts stores and they were both too big and would not fit.

I was checking out the LMC catalog and I found that there are tanks with and without vent hoses(evaporative emission control). Mine has a vent hose. But according to their catalog, those tanks are only on 70-71 trucks.

This truck is not original and I don't have a lot of information on its past. I do know it was partially restored when the previous owner bought it. Is it likely that whoever did the previous restoration put a 70-71 cab on a 69 frame? Is there anyway I can confirm this? The front end is a 69-70 front end. The plate with the VIN number is not mounted to the cab, it is laying in the glove box.

Also, is the fuel cap smaller on the tanks with the vent hoses? Thanks for any help.

John

should be the same. NAPA has the stock Caps, we do to but they come from Napa. They are made by Stant Mfg.

The 68's and earlier are a little diff in height but otherwise they should be the same from 1969 to 1972

[JMRide76]

I drained the old fuel out of the tank, but did not do anything to clean the tank. I also replaced all the old fuel lines and put a new fuel filter on it. Hopefully I don't have any issues with old/dirty fuel.

[Shyguy]

There is a difference between the gas caps. If memory serves me right 67-70 were different than 71-72. Some '71-'72 were different depending if they had the vented or unvented tanks.

The tanks are interchangeable, I have a '71 vented tank in my '67. My '71 has an unvented tank.

Danny

[mbgmike]

Originally Posted by Shyguy

There is a difference between the gas caps. If memory serves me right 67-70 were different than 71-72. Some '71-'72 were different depending if they had the vented or unvented tanks.

The tanks are interchangeable, I have a '71 vented tank in my '67. My '71 has an unvented tank.

Danny

all the part numbers and dimensions are all the same from all our manufacturers for years 67 to 72 according to partslink and the other part systems we use. Not one of them specify if its vented or non vented.
The only difference is the height on the 67 but otherwise same dimensions for the other 1/2 ton years.

Now 3/4 tons have a differant part number. We sell the tanks and you are correct. I will look some more but so far all the same.

[nicolas72gmc]

The filler neck is a different size on my 68 than what is on my 72. I tried switching the caps once and no go!

[mbgmike]

Originally Posted by Shyguy

There is a difference between the gas caps. If memory serves me right 67-70 were different than 71-72. Some '71-'72 were different depending if they had the vented or unvented tanks.

The tanks are interchangeable, I have a '71 vented tank in my '67. My '71 has an unvented tank.

Danny

Ok I just rechecked with Stant.

67 68 69 70 are part 10623
70 w/o calif emisions is part 10623
with emissions they do not make
1971 is part 10704
1972 is part 10742

So you are correct on the 67 to 70 years
the 71 and 72 are both differant
I learn something new every day.

[Shyguy]

Just drifted back in to see what information was posted.

I knew the gas cap on my two trucks were different and my son has run across the problem also.

It seems ever time I log on to this site I learn something new, that is why I like it so much, well visiting with you all is great too.

Danny

[mbgmike]

Originally Posted by Shyguy

Just drifted back in to see what information was posted.

I knew the gas cap on my two trucks were different and my son has run across the problem also.

It seems ever time I log on to this site I learn something new, that is why I like it so much, well visiting with you all is great too.

Danny

Now I just looked the c20's up and 1967-72's are all part 10623 so the 3/4 tons are the same. makes sense since most of the emissions started with the 1/2 tons

[unclewatts]

Here's what I know. Regardless of year, if you have a non EEC tank you use a vented cap. If you have a EEC tank you HAVE TO use a non vented cap otherwise the EEC system won't work.