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Chasing Down Leaks - My '70 Mustang

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One thing I really hate is a leaky car.  I don’t like it when stuff leaks inside the car and I don’t like it when stuff leaks out of the car.

I have a friend that alway says…”Hey…old cars leak.  That’s just what they do.”   To this I normally just respond with “Yeah…I guess so.”  I say this because he has pride in his work he does on his cars and I’m not going to poke at him about it.

What I want to say is “Bullstuff!!!!” Not this day in age, there all kinds of reproduction parts and hoses that can be molded and even entire businesses that make custom hoses.  If it’s a gasket that’s leaking you can make your own, there’s all kind of gasket material on the market.

If you remember back a bunch of post ago, you may recall my power steering issue with my C4 Vette.  Oh…yes…my poor old vette (which now has a new home), leaking everywhere!!!!.  I hated that, but it was all fixable, right down to having a place in town customize a power steering hose ( it didn’t actually get that far, the oddly shaped hose turned out to not be the issue.).

The reality is that chasing down a leak is sometimes difficult, almost always time-consuming and the likelihood that it will be expensive is high.  So, no old cars don’t have to leak. 

What old cars do do (that’s just as funny to type as it is to say) is vibrate.  My ’70 Mustang is mostly stock parts, with the exception of polyurethane motor mounts, and it will shake stuff loose, is it a pretty raw machine.  A good portion of leaks can be attributed to that alone.

A few weeks ago, I notice a dime sized dot of oil in my driveway….errrkkk….no I’m not a neat freak, my drive has spots (been meaning to get it power washed), but with my older cars I like to keep an eye out for issues.  So I climbed under the car and looked around and it appeared that the leak might be from the oil plug it’s self.   So I grab my 5/8 “ open end wrench and gave it a bit of a crank.  Now you have to be careful, especially with the type of oil pan I have (aftermarket chrome)  as it can get out of shape if you over torque the drain plug and really leak. I wiped down the pan so I could tell later on if there might be another leak.

Chrome Oil Pan and Plug


A few drives later I noticed another dime size drip. Only this time  it was a bit further back.  OF NOTE:  My driveway is sloped, and pretty good incline at that.  This causes a bit of a problem determining exactly where liquid might originate, that whole gravity thing, ya know.  This drip did seem a bit further back then the last.

Again I check the oil pan and this time the oil pan gasket between the engine and the block. Nope no oil.  So I go topside and start checking the  valve covers.  And sure enough there, there appears to be a leak in the rear of the left value cover.  Not really a big deal, looks like it’ll just need new valve cover gasket, this 302 engine is wide open in the engine bay with lots of room (nothing like the 84 Vette was to get to).

Lots of room in this engine bay to work.


Valve Cover, you can see the bit of oil grunge along the bottom.


 I then recalled that FelPro gaskets were used and I specifically chose the type used on drag cars, designed so that you can pop the valve covers over between heats to make adjustments.  This particular set of valve covers that I purchased when restoring the car came with bolts that tighten with an allen wrench.

Screw with allen wrench (or hex wrench).


 Just in case:

Allen Wrench/Hex Wrench


Hexagon end of allen wrench


So I thought…to myself (really….can you think to anyone else?) “I wonder if they are all tight?”  Sure enough they were all loose.  Hence the oil leak.   I tightened them all down, wiped down the engine where I could reach and drove it a couple of days. No leaks!!!  Now I make it a habit to check those every so often.  This is BTW a good tip if you drive your muscle or vintage car. 

Now the latest leak, I noticed a couple of days ago.  I check the liquid laying in my drive (only about the size of a quarter) and it was power steering fluid.  I’m thinking oh…NO..not again!!!  I didn’t even look under the car and went straight to the computer and did a quick search for new power steering parts for my 70 Mustang. What I found wasn’t horrible, as in, well no retirement for me, got to fix up this ‘stang, but bad enough price wise to see if it was repairable.

So I crawled under the Mustang (or hunk of iron, as my wife calls it…or maybe she was calling me the hunk  :^ ) and took a look.  Yup, there was a leak but it appeared to be coming from the flared steel hose fitting going into the power steering unit.

Steel hose and the leaky mess.


A couple turns with a 1/2″ open end wrench and again wiped down area.   I keep checking back to see if any new leaks appear.

I can say… right now…. that my 70 Mustang doesn’t leak….I don’t think!!!

So now I stand corrected, sort of.  Old car do leak, hey new cars leak!!  However, they don’t have to stay that way. 


1.  Check under your muscle or vintage car for any liquid (hey…it’s ok if is just water from you AC..usually) on a regular basis.

2.  Get under the hood and after your ooo’ss and aaahhh’s at your magnificent creation, tight things up. ( I always ooo  and  aaahhh!!!)

3. Get the car up in the air “”SAFELY”" and check the fittings you can’t see or reach from the top side.

4. Chase down the leaks and clean the area to make checking for a continued leak easier.

Thanks for reading.


If a 40 year old plus car does not leak, it's empty.

 ;D   lol

I agree that old cars don't HAVE to leak.  I have a tiny bit of leaking around my transmission, but it's not enough to worry about.  I just take it to the car wash with the wand and spray a little degreaser on the tranny and wash it off about once a year.  It's just enough of a leak to collect a little dust.   So far, my engine doesn't leak anything.   I replaced the valve cover gaskets awhile back when I repainted the covers,  and so far, they seem to be holding.  Yup, the older they get, and the more you drive them, you are going to get some leakage.  The gaskets get brittle, so you need to pull some maintenance and replace them every now and then.  The same thing with hoses.  The good thing about these old classics is that most of us don't have a car payment, so can put some jingle in a jar and save for these kinds of repairs. 

Leaks are annoying-but tightening things down to stop a leak can be a hazard in its own right.

If you are snugging a line, fitting or bolt that is loose, you can indeed stop some leaks.

If a gasket is brittle or an o-ring etc, you can create a new and more serious leak.

I don't mind small leaks that I can identify and that don't threaten reliability.  A dime size drop of oil is essentially a non issue in my book.  Heck breather caps drip that from accumulated vapor when the PCV system isn't pulling it in through the carb.


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