Coolant leak somewhere between transmission and engine + power steering boot leak?

[kevboost7]

Crawled underneath my car to see where the drops of liquid is coming from. I have 2 issues.

1. There is a coolant leak somewhere between the engine and the transmission. I have no idea where this is coming from. It seems very slow. Is it possible that the coolant is leaking between the transmission and the engine?? (idk if that's a dumb question). Its only on the drivers side. the passenger side is clean. Last year i did a complete coolant hose overhaul and replaced everything with silicon tubes. 

    

2. I noticed that the boot on my power steering rods are torn. Is the grease underneath the car just from the boot being torn? or is the power steering leaking itself? Is it supposed to be greased and lubed up inside the boot?

[GTSBoy]

1 hour ago, kevboost7 said:

Is it possible that the coolant is leaking between the transmission and the engine??

Yes it is possible. There is a welch plug on the back of the block (behind the flywheel).

1 hour ago, kevboost7 said:

Last year i did a complete coolant hose overhaul and replaced everything with silicon tubes. 

That's the other possibility. If the hoses were original, then you could easily figure that one is about to pop. Because you have definitely been in there and changed them, it is eminently possibly that the leak is from one of the heater hose connections at the rear under the inlet manifold

 

1 hour ago, kevboost7 said:

I noticed that the boot on my power steering rods are torn. Is the grease underneath the car just from the boot being torn? or is the power steering leaking itself? Is it supposed to be greased and lubed up inside the boot?

The grease under your car could be because we're talking about a 35 year old car here.....

PS fluid should not escape from a torn boot, but PS fluid might be escaping from the torn boot. We're talking about a 35 yo car here.

[kevboost7]

Good points GTS.

Is it possible to replace the welch plug on the back of the engine while it's in the car?

So let me understand. In normal conditions, inside of the boot, the rod should be clean and have no grease or PS fluid on it? 

 

[kevboost7]

It can't be from the heater hoses. I checked and its clean. 

[kevboost7]

I dont even know where the welch plugs are at on the engine. What are they for? Does anyone have a diagram?

[Duncan]

As well as the heater hoses, unfortunately there are multiple small coolant hoses under the plenum at the rear of the engine, real pain to change engine in, if one was leaking they would drip onto starter then down into that area.

Welch plugs are the series of brass or steel plates that block off holes that were needed to machine the block. Per this pic from elsewhere on the site there are 3 at the rear of the motor, in this case the one in the bell housing is missing. Also the top one is unusual because it goes to the head oil space not coolant galleries, that is where a rear drain/breather is often placed.

It is much less likely to be leaking from a welch plug unless your motor has been rebuilt at some stage.

Re the power steering rack, you just need to get the boots replaced before too much shit gets in there. The boots protect the inner rack end ball joint, not sure how much grease they are meant to have but it can't be nothing as they move. Genuine is better than aftermarket for boots because a lot of the aftermarket stuff uses much harder rubber that doesn't last.

[kevboost7]

4 hours ago, Duncan said:

As well as the heater hoses, unfortunately there are multiple small coolant hoses under the plenum at the rear of the engine, real pain to change engine in, if one was leaking they would drip onto starter then down into that area.

Welch plugs are the series of brass or steel plates that block off holes that were needed to machine the block. Per this pic from elsewhere on the site there are 3 at the rear of the motor, in this case the one in the bell housing is missing. Also the top one is unusual because it goes to the head oil space not coolant galleries, that is where a rear drain/breather is often placed.

It is much less likely to be leaking from a welch plug unless your motor has been rebuilt at some stage.

Re the power steering rack, you just need to get the boots replaced before too much shit gets in there. The boots protect the inner rack end ball joint, not sure how much grease they are meant to have but it can't be nothing as they move. Genuine is better than aftermarket for boots because a lot of the aftermarket stuff uses much harder rubber that doesn't last.

Duncan, thank you for this. The previous owner did say that he paid a shop to rebuild the engine with forged components. I have no way of verifying this, but I know that the shop wasn't detail oriented as there are mix n matched screws everywhere. And they did not replace the coolant water hoses or metal line under the plenum that was rusted. Last year, i replaced all the coolant hoses. 

As for the welch plugs. . in my drawing, is this where the transmission connects to it? 

[Duncan]

yeah pretty much, although the plate is rounder and picks up the right block webbing too. If you look closely you can see a missing welsh plug in this pic; if that is the issue in yours it is gearbox out, clutch/flywheel off to replace the leaking one, but that is much less likely than a water hose

BTW changing the external head welch plugs from inside the car is easy if you have no dash in your race car, just need to holesaw the firewall in the right place and it is easily accessible. May not be so practical in a road car.

[TurboTapin]

18 minutes ago, kevboost7 said:

Duncan, thank you for this. The previous owner did say that he paid a shop to rebuild the engine with forged components. I have no way of verifying this, but I know that the shop wasn't detail oriented as there are mix n matched screws everywhere. And they did not replace the coolant water hoses or metal line under the plenum that was rusted. Last year, i replaced all the coolant hoses. 

As for the welch plugs. . in my drawing, is this where the transmission connects to it? 

Confirmation of non OEM pistons and rods could easily be done by popping a sparkplug out to verify piston top and oil pan to confirm rods. You could also probably just fiddle with a borescope through your oil drain actually without even removing the pan. 

[kevboost7]

56 minutes ago, TurboTapin said:

Confirmation of non OEM pistons and rods could easily be done by popping a sparkplug out to verify piston top and oil pan to confirm rods. You could also probably just fiddle with a borescope through your oil drain actually without even removing the pan. 

what would i be looking for? shiny new looking pistons? do pistons have markings on them to indicate a brand or something?

[kevboost7]

Also, while i'm replacing the inner tie rod boot, anything else i should replace? the place i buy parts, charge shipping so i'm trying to bulk buy everything to avoid paying shipping twice lol

[Duncan]

Yes, although they are different per manufacturer. 

standard rb26 pistons are marked 05U and have a dot to align piston to front of motor.

[Duncan]

1 minute ago, kevboost7 said:

Also, while i'm replacing the inner tie rod boot, anything else i should replace? the place i buy parts, charge shipping so i'm trying to bulk buy everything to avoid paying shipping twice lol

either nothing, or if you want to be proactive both inner and outer tie rod ends both sides as they are wear items and it may be a long time since last replacement (if ever). If you replace the tie rod ends you will need a wheel alignment.

[Max32]

Get an endoscope and look under the plenum/ on top of starter motor, if you have coolant (stains) there its one of your silicone hoses.

[kevboost7]

i looked everywhere.. under the plenum is dry. Its only around the transmission area. I'm so puzzled. I tried to get a endoscope to look at it, but its too dark to tell. At this point, i don't think i can see where the leak is coming from unless i remove the engine.. is it possible to get to the back of the motor without removing it? I'm assuming its the half moon things, but i've never seen them with my own eyes. 

[GTSBoy]

The half moons don't have coolant behind them. They back onto the camshaft tunnels and have oil behind them.

The previously mentioned welch plugs on the back of the engine could be it.

It's a gearbox out job at the minimum, just to find out if you need to do them.

[joshuaho96]

3 hours ago, kevboost7 said:

i looked everywhere.. under the plenum is dry. Its only around the transmission area. I'm so puzzled. I tried to get a endoscope to look at it, but its too dark to tell. At this point, i don't think i can see where the leak is coming from unless i remove the engine.. is it possible to get to the back of the motor without removing it? I'm assuming its the half moon things, but i've never seen them with my own eyes. 

Did you actually inspect everything under the plenum? The area at the back of the engine is a mess of coolant pipes. There's a Y-pipe for coolant return next to the wastegate vacuum pipes which can pinhole leaks from corrosion or mechanical stress cracks the weld/brazing for the joint. Also the rear block fitting for coolant could also leak. It also has a Y-pipe as well. As others have said it is also possible that the core plugs have corrosion so they're leaking coolant as a result. You can try to fix it with RTV but getting access especially for the back of the engine will probably require engine removal.

Edit: Pic to show what I'm talking about:

Edited October 16, 2023 by joshuaho96

[kevboost7]

On 10/16/2023 at 5:07 PM, joshuaho96 said:

Did you actually inspect everything under the plenum? The area at the back of the engine is a mess of coolant pipes. There's a Y-pipe for coolant return next to the wastegate vacuum pipes which can pinhole leaks from corrosion or mechanical stress cracks the weld/brazing for the joint. Also the rear block fitting for coolant could also leak. It also has a Y-pipe as well. As others have said it is also possible that the core plugs have corrosion so they're leaking coolant as a result. You can try to fix it with RTV but getting access especially for the back of the engine will probably require engine removal.

Edit: Pic to show what I'm talking about:

Yes, last year i had all the hoses replaced with new silicone ones. And i even replaced that silver hard vacuum/coolane pipe that all the hoses connect. That hard pipe was corroded. Everything under the plenum is 100% dry. 

This is a silly question, but the transmission dosent get any coolant does it? 

[joshuaho96]

1 hour ago, kevboost7 said:

Yes, last year i had all the hoses replaced with new silicone ones. And i even replaced that silver hard vacuum/coolane pipe that all the hoses connect. That hard pipe was corroded. Everything under the plenum is 100% dry. 

This is a silly question, but the transmission dosent get any coolant does it? 

No, not the manual transmissions. I have to check for the automatics but most likely instead of sending coolant under the car to the transmission oil heat exchanger they would send transmission oil lines going forward into the radiator instead.