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Do I need to worry about this oil leak?

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tlsmart1

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Hello. I'm a new owner of a B and don't have a lot of mechanical experience. I've read that it's common for MGBs to leak oil, but is this one ok? I've owned my car for a week and it started leaking yesterday. Today it was dripping at a rate of about 80 drips per minute onto the garage floor. I opened the hood and saw it dripping from the part I've marked with an arrow in the photo. The British car garage that I'm using for service is about 100 miles away - any worries about driving it there?

7827_180490746270_564376270_4234727_4980537_n.jpg
 
That's your heater valve, and it's leaking engine coolant. The leak is nothing to be concerned about on its own, but the problem is the distributor directly beneath it. Moisture will at some point work its way in there and the car will stop running. If this happens, you only need to dry it out under the cap and lubricate the distributor when you get a chance. Then again, if you've installed electronic ignition such as Pertronix, then moisture can destroy it completely and there is no fix other than replacement of the electronics.

I would recommend replacing the valve at your next opportunity, and also the heater hoses while you're at it. The one I can see looks pretty crusty. You will need to order the valve and a gasket, and buy some Permatex blue gasket sealer. Smear a very light coat on the gasket before assembly. Try to prevent any from squeezing inside the water passage when you tighten the valve down. The valve is held on by only two screws, and the control cable is anchored by one. the lower valve screw is the toughest one to get at. An ignition wrench or sometimes a thin 1/4" drive socket will get at it.
 
Steve is exactly correct and has given good advice.

The stuff leaking is not oil; it's anti-freeze.

The heater control valve is exactly like a facet in your house. When you move the heater control on the dahboard, this valve opens (and lets hot engine coolant into the heater inside your car).

Have you ever seen old-fashioned houses that have a cast iron radiator in each room? Many times, each room-radiator will have a valve on it to allow more hot water to flow (to make the room warmer). This valve on your MGB does the same thing.

Anyway, if you drive it in the meantime, check your radiator level frequently. You don't want the car to get too low on coolant (or it will overheat).

Also, if you move the heater control on the dash to a different postion, you might find that this valve will drip a little less (not that this would be a permenant "fix").

~Moss Motors~ lists this valve at under $30 (part #23 in the link) but there are many other places you could get it too.

Here's what a clean MGB heater control valve looks like (below):

BHA5298_lg.jpg
 
Also, did you realize that your vacuum advance hose is missing from that picture. That, in and of itself may not make a massive difference in performance (depending on the year of your car) but if the vacuum advance port on the manifold or carb is disconnected you may have a vacuum leak which does cause a lot of trouble.
 
Back when the things were Unobtanium I made a mold to cast my own diaphragms with Devcon rubber goop. Now the silly things are cheap!

I carry a "blanking plate" and gasket in the on-board spares kit, along with two shorter bolts, too. Learned THAT lesson waaay early. And an old sparkplug (porcelain end) in the return side hose with existing clamp! "Press on Regardless!" :wink:


<span style="font-style: italic">EDIT: A 7/16" quarter inch drive swivel socket is a GREAT aid for removing the valve from the head.</span>
 
I might add, based upon experience, that if what is leaking out APPEARS to be oil, and not identifiable as "green", you may have a serious issue with DOA coolant.
When that stuff "turns" it can lose it's anti-rust agents and actually do the opposite.
To keep you from running off screaming into the woods, I won't go into the Merck Manual description.

However!

If it ain't green, flush it until clear.


Oh, and whatever that is jammed next to the hex on the plug right above the heater tap.....
Looks like it could be a small Phillips screw.....might want to save it if you lost it from somewhere else.....
 
Thanks a lot.

I couldn't find anything in the Haynes manual regarding the vacuum advance, and I'm not sure how you identified that is was missing in the last photo. Would either of these indicate whether the vacuum advance port is missing on the carbs/manifold? My car is a 1973, if that helps.

7827_181048886270_564376270_4239630_7157099_n.jpg

7827_181048891270_564376270_4239631_7723637_n.jpg
 
Thanks for all the advice. The thing wedged by the spark plug turned out to be an electrical push connector (from when it had an electrical upgrade, I assume). I think the fluid is fine, I just couldn't tell the color when it was on the garage floor and assumed it was oil.
 
tlsmart1 said:
7827_180490746270_564376270_4234727_4980537_n.jpg
Click to expand...

If you go strait down from the boot at the number 4 spark plug to the distributor you will notice a round attachment on the distributor pointing strait up with a nipple on it. That should be connected to a port on the rear portion of intake manifold.
 
As Stewart says, there should be a hose attached to the distributor vacuum advance port (below #4 plug) that goes straight up from there, arcs over the valve cover, and attaches to a port on top of the intake manifold. I can't tell from the photos what is happening at that intake manifold port but I'm guessing that it has a simple plug on it. 1973 was when the factory was fiddling with advance settings to try to reduce emissions rather than increase performance so there may not be a huge advantage in reconnecting it (there would be a huge advantage for earlier vintages). Also note that there is a distinct possibility that if never serviced the vacuum diaghragm may have failed and reconnecting would do nothing at all unless you had the distributor rebuilt. Just make sure that the manifold port is either connected to the vacuum advance unit or is plugged securely.
 
As long as you've determined that's the part that actually is leaking the above advice has you covered.

To be sure it is coolant and not oil place white cardboard under car and catch the drips. It could in fact be oil (jet black, probably) simply leaking behind that heater valve - which would indicate not so simply a head gasket leak. Best to know what you are dealing wit hbefore fixing something that isn't broke and not fixing smething that is. Coolant leaking except through head gasket when combined wit hoil should be very close to same color as what is in radiator (green/blue wit h a little rust added in)
 
Thats what your looking for for the vacuum line connection on the manifold. If you have a timing light it's worth hooking it back up. You may also want to have it rebuilt over the winter. Since your in the MN advance distributors is dang near in the citys and can rebuild the distributor to a better than new condition and really wakes up these old cars.
 
tlsmart1 said:
Is this the intake manifold port? It has a little rubber cap.

7827_181580606270_564376270_4245801_3146343_n.jpg
Click to expand...

That's it....do you know how to pull the distributor without affecting any settings? If you do, pull it & suck on the vacuuum advance to see if it works.
 
OR leave the distributor in and hook a hose to it. Remove the distributor cap and see if the plate that holds the points moves when you suck on the hose. Bob
 
Good one, Bob....I'd never thought of doing it that way.
 
Back in the "old days", in the shops, it was de rigueur to put a Mity-Vac or similar vacuum pump up against the advance and make certain it worked AND held during tune-ups.
Generally, if you had a mechanic that actually thought, he did it with the cap off and abserved the movement of the plate.

I still do that on every tune-up or check for poorer performance than one thinks he or she should have.

How I found the advance blown on my LBC about three weeks after I bought it.
 
Although I'll bow to wiser heads, the '73 model had a totally hackneyed vacuum advance (they may have even had a bit of vacuum retard) due to new smog requirements. Hooking the thing back up may in fact do nothing for performance. I'd advise consulting some more knowledgeable folks (i.e. the folks at advanced distributors?). It might even make more sense to have the advance rebuilt so as to give an earlier non-stock curve.
 
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