Leaky small block

[Dutch Rutter]

Hey Everyone,

After some time of enjoying the leak free truck it appears to have sprung a new oil leak.
I am seeing large dark drips (darker then my engine oil) off my lower radiator hose which appear to be coming down the back (end from the water pump). I am also seeing the same large, dark drips from the bottom of my fuel lines right off the fuel pump.

And also a coolant leak somewhere, only place I am seeing coolant is on the transmission lines at the back of the engine oil pan. Since I'm not seeing the normal thermostat housing leak or anything else I'm thinking its time for a new water pump.

Any ideas on this Engine oil leak though? My intake and valve cover gaskets are newer and not showing signs of leaking, I'm not loosing a lot of oil or having oil and coolant mix so I do not think its the head gaskets. Rear main, Oil Pan and Oil Pan gasket also are new and no signs of leaking.

So where to start? timing chain cover and gaskets? or is there a gasket at the fuel pump or fuel pump plate that should be replaced??

 

[chengny]

Hey Everyone,

After some time of enjoying the leak free truck it appears to have sprung a new oil leak.
I am seeing large dark drips (darker then my engine oil) off my lower radiator hose which appear to be coming down the back (end from the water pump). I am also seeing the same large, dark drips from the bottom of my fuel lines right off the fuel pump.

And also a coolant leak somewhere, only place I am seeing coolant is on the transmission lines at the back of the engine oil pan. Since I'm not seeing the normal thermostat housing leak or anything else I'm thinking its time for a new water pump.

Any ideas on this Engine oil leak though? My intake and valve cover gaskets are newer and not showing signs of leaking, I'm not loosing a lot of oil or having oil and coolant mix so I do not think its the head gaskets. Rear main, Oil Pan and Oil Pan gasket also are new and no signs of leaking.

So where to start? timing chain cover and gaskets? or is there a gasket at the fuel pump or fuel pump plate that should be replaced??

There is one opening that connects the internal lube oil system to the exterior of the block - and the only thing that keeps the oil from leaking out is a 3/8" - 16 bolt (NC threads). There are no o-rings, gaskets or any other type of seal used on it.

I don't know for sure that GM did this purposely, but (there are 4 of these, used to mount various auxiliaries/bracketing) they drilled the top RH bolt hole all the way through. It terminates in a hollow cavity - the one that allows the fuel pump push rod to transit the block and make contact with the pump's rocker arm. It is probably just splash lubricated, but regardless, that cavity is always supplied with oil.

Anyway over time, folks discovered that when mounting a new fuel pump - if the push rod kept falling out - a longer than designed bolt could be temporarily screwed into the top hole (adjacent to the fuel pump). The longer bolt kept the push rod pinched in place until the pump was made up.

In theory, the long bolt would then be replaced - by one of the correct length.

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The three indicated with arrows are blind drilled, it is only the one circled that is open to the engine's oil system. It is probably not the source of your drips, but all the spots you mentioned - as having noticed oil - are right there in the area. It is an easy thing to check - much easier the timing chain cover or the fuel pump gaskets.

 

[4WDKC]

Are you sure its not coolant leaking from the wp down the block and lower hose getting contaminated with oil from previous leaks or grease and then dripping on the ground?

 

[Rusty Nail]

Antifreeze weepin out the leak hole!

 

[Dutch Rutter]

Thanks all!

I myself have used the longer bolt trick for holding the fuel pump rod in place. Not on this motor yet though so I will be sure to check that out. I do believe this fuel pump was replaced not too long before I bought the truck so I wouldn't be surprised if it was missed or left loose. Would putting some RTV on the bolt (kind of like the center intake manifold bolts) be a bad idea?

I am pretty sure it is oil and that the coolant leak is from the weep hole in the pump itself like Rusty said. However, I will not rule that out as being a possibility either 4WDKC. Since I need to replace the pump anyway I'll be addressing both this coming week once parts arrive. I would much rather prefer it being something like these two areas then having to pull the one piece timing cover off.

 

[Dutch Rutter]

Welp stuck my head down there after work... Amoungst all of the mucky oil I found that sure as sh*t no bolt what so ever.. I thought I would luck out but looks like I also don't have a spare anywhere to be found. So I'll be making a trip to the hardware shop this week to get one.

Will report back once I get one in there, things somewhat cleaned up and a few drives in.

 

[K201979]

Sounds like u did luck out, just not as much as u had hoped.

 

[Dutch Rutter]

Got my bolt in with some RTV around the threads. Will be keeping an eye on it to see if my oil leak is fixed.

I was wondering how you guys are doing your coolant overflow bottles?
I am used to the bottle on the passenger side fender with the tube going from the Rad into the bottom of the bottle which worked well as long as the bottle was not cracked. Mine has a bottle between the rad and the passenger side battery tray, the tube from the rad goes through the top of the bottle and into the coolant. This bottle also has a overflow thing where if it gets too full it dumps the excess coolant.
Is this normal or should I be looking at a different way to do this?

Edit: This is what mine looks like

https://www.classicparts.com/1981-8...F7aTTuNbVbkWoKYEcrRxXo5J5g-T4QbBoCd1IQAvD_BwE

 

[77 K20]

On my '77 I had one kinda like yours- it was between the radiator and the battery tray. I take it off road a lot. Hitting bumps makes the antifreeze slosh around and spill all over. I ended up buying the type that goes on the fender (85+).

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And at least in my case it didn't fit flat/perfect on my inner fender liner. Being that your truck is from the 80's maybe it will fit better. I had to stack some washers under one of the tabs to make it set level. Been real happy with it though.

 

[Dutch Rutter]

Thanks 77 that is the exactly the same reason I am wanting to change my bottle setup around. I think I will go with the newer style like you did. I will have to drill the holes and remove my factory bottle jack (which probably wont work on my lifted truck anyway) But I think it'll work out pretty nicely.

When I was looking online for one of those to buy other then LMC I found some aftermarket aluminum setups similar to this one https://www.amazon.com/gp/product/B07F1F7BDY/ref=ox_sc_saved_title_1?smid=ADS6910RW2FED&psc=1 Which looks alright and usable but I don't know about mounting it or the added bling factor. I'd personally rather keep with one of the original styles.

 

[Chevyguy]

Welp stuck my head down there after work... Amoungst all of the mucky oil I found that sure as sh*t no bolt what so ever.. I thought I would luck out but looks like I also don't have a spare anywhere to be found. So I'll be making a trip to the hardware shop this week to get one.

Will report back once I get one in there, things somewhat cleaned up and a few drives in.

Invest in a flourescent dye leak test kit. You put dye in your oil after you clean your engine off of all the leaked oil. Drive your truck around for awhile and then check for leaks with the kit included black light, the leaks location will be exposed and glow. Auto part stores sell the kits.

Clayton

Sent from my LG-K450 using Tapatalk

 

[Dutch Rutter]

I was thinking of doing just that.

So far nothing I have done has helped stop this leak now it seems to be high on the passenger side. but all of the normal areas are clean, intake, sending unit, valve covers, and dizzy. I am seeing oil on the starter and transmission inspection cover. This make me at least very suspicious of my heads. Since these are the light 882 heads. Being that they are known to crack I am thinking they are my culprit. Either cracked or warped. I am not getting any fluid mixing. Is there any other way besides pulling these things to check them? If I pull them I will not be putting them back on so I'll need to get a set of heads in hand to put on in their place.

 

[shiftpro]

Got my bolt in with some RTV around the threads. Will be keeping an eye on it to see if my oil leak is fixed.

I was wondering how you guys are doing your coolant overflow bottles?
I am used to the bottle on the passenger side fender with the tube going from the Rad into the bottom of the bottle which worked well as long as the bottle was not cracked. Mine has a bottle between the rad and the passenger side battery tray, the tube from the rad goes through the top of the bottle and into the coolant. This bottle also has a overflow thing where if it gets too full it dumps the excess coolant.
Is this normal or should I be looking at a different way to do this?

Edit: This is what mine looks like

https://www.classicparts.com/1981-8...F7aTTuNbVbkWoKYEcrRxXo5J5g-T4QbBoCd1IQAvD_BwE

I wish I got here sooner, I would have advised to stay from RTV for thread sealant. It is better than nothing but will weep eventually. The select product for thread sealant is the white Permatex product. And must clean out the treads with brake cleaner and dry before applying. Anyway, for the most part you have sealed your major leak, right on,

 

[shiftpro]

The oil in under your tranny inspection cover could be from above... rear of intake manifold and/or distributor. Typical place to leak..

 

[Dutch Rutter]

Thanks @shiftpro I'll be sure to pull it back out clean things up and use some in place of the RTV. I do have Teflon thread tape and probably should have used that from the start.

So I just got back from rolling around under and ankle deep inside of the truck with a large roll of paper towels wiping things down. The leak seems to have slowed down but My starter, trans, inspection cover, and front drive shaft are still soaked while the engine pan remains clean.

My white paper towel treatment shows some very miner seepage from the back bottom corner of the passenger side valve cover, (not nearly enough to worry about)
lower edge of the cylinder heads, as well as the bottom edge of the intake manifold and the sending unit on the rear of the block are all completely dry other then some grime.
However, my timing cover is pretty saturated all the way around as well as the pan gasket showing signs of oil running down it from the timing cover. So I think that will be my next focus. In my seemingly never ending pursuit of the end of engine leaks.