Coolant leaks out from here

[vkmotorsports]

Hello
I have a 2001 Boxster S with ~143,000 miles on it.

For the last 2 months (and I have barely been driving this car more than 10-20 miles a week during those months) i have had a serious coolant leak.

Most of the coolant leaks out as soon as the engine starts running from the middle bottom of the car (picture attached). The coolant tank then drops to much below the minimum level.

When I was jacking up the car as well some of the coolant poured out but I think that was just residue from the earlier leaks collecting there.

This problem did not exist in May, but has started since June. At first I thought the issue with low coolant was due to excess heat and evaporation. But that is not the case as now I can see a leak happen as soon as the engine starts.

I don't know what has changed. I have never done anything to the car since May besides getting an alignment at a Firestone while getting new tires installed by them.

I have also never opened up the undercarriage of the car or got work done there. I have done the oil changes myself and the brake pad changes myself.

How do I figure out what the problem with the coolant leak is ? Is it some damage caused during the alignment ? I cannot prove that is what has happened at all, as it is just conjecture on my part.

What is the best way to go about diagnosing the problem.

Please advise.

[Keith Newby]

I think it may be time to take to consider replacing the water pump.

[vkmotorsports]

Originally Posted by Keith Newby

I think it may be time to take to consider replacing the water pump.

is water pump failure causing the leak or is the process of fixing the leak an opportunity to also replace the water pump ?

[blue62]

Originally Posted by vkmotorsports

is water pump failure causing the leak or is the process of fixing the leak an opportunity to also replace the water pump ?

First thing to do is a visual inspection of the suspected area of the leak.
If you find nothing obvious (like a leaking hose).
Then get a coolant system pressure tester.
Places like Harbour freight have them for a reasonable price.
You can test just about any coolant system with them as well as the coolant cap.
With the test kit is it easy to find leaks in coolant systems.

People will say change this or change that. That is Poor way to do things.
Find the cause of the problem then fix the problem.

[vkmotorsports]

Originally Posted by blue62

First thing to do is a visual inspection of the suspected area of the leak.
Then get a coolant system pressure tester.
Places like Harbour freight have them for a reasonable price.

People will say change this or change that. That is Poor way to do things.
Find the cause of the problem then fix the problem.

I went and purchased the Harbor Freight radiator pressure test kit and will try it out.

Agree that I want to find the cause first before trying out solutions.

Thank you.

[blue62]

Originally Posted by vkmotorsports

I went and purchased the Harbor Freight radiator pressure test kit and will try it out.

Agree that I want to find the cause first before trying out solutions.

Thank you.

From what I can tell in your picture I am looking at the the area where the aluminum pan (brace) and the plastic under body trays meet.
Remove that plastic under body tray and you should see where a number of coolant hoses meet up.
Then top your coolant system off with distilled water and pressurize the system with your tester. You should have no problem finding your leak..

Once it is repaired then us the tester to again pressurize the system so you can make sure everything is ok.

[Stl-986]

First thing to do is to STOP driving the car

Next - remove belly pans
Next - Look to see where coolant is coming from

[ike84]

+1 to blue and Stl's comments. Remove belly pans, pressurize the system, localize the leak. DO NOT DRIVE UNTIL IT'S FIXED.

Sent from my SM-G970U1 using Tapatalk

[blue62]

VK,

I should have mentioned this in my first post.

Another item that is a common coolant system problem is the plastic coolant fill tank in the rear trunk.
They develop hairline cracks with age.
You should remove the carpet and the sub floor in the trunk.
Strip everything out Down to bare metal.
Then when you pressurize the coolant system you can check the plastic coolant tank as well.
Keep me posted..... if you need to replace the coolant tank I can give you a few pointers.

[vkmotorsports]

Originally Posted by blue62

VK,

Another item that is a common coolant system problem is the plastic coolant fill tank in the rear trunk.
They develop hairline cracks with age.
You should remove the carpet and the sub floor in the trunk.
Strip everything out Down to bare metal.
Then when you pressurize the coolant system you can check the plastic coolant tank as well.
Keep me posted..... if you need to replace the coolant tank I can give you a few pointers.

Thank you all. blue62, I filled up the tank all the way, I did the pressure test on the tank as per the Bentley manual using the harbor freight kit and it did not show any sign of leaks in the tank area. At least the tank is not cracked and was still full after the pressure test.

I flipped up the bleeder valve locking clip a couple of times and there were no leaks and drips initially when I started and moved the car back and forth in my garage to driveway. I drove the car for 0.5 mile locally, and saw no leaks or drips at all. Coolant level looked full in the tank exactly as it looked when I had filled it up

Drove it for 5 miles after waiting 30 min, and making sure there were no drips or leaks.

After the 5 mile drive is when I noticed that the dripping began again in 3 different spots which coincide with hose placements most likely - 2 in the middle of the car and one near the front of the car towards the radiator.

I am waiting for the car to cool down to check the coolant level after the dripping has stopped. Most likely the hoses are failing when the car gets hot.

Then I will redo the pressure test and look for hose leaks again.

I am contemplating that in a hot condition the hoses may be expanding to cause dripping/leaking and when cold the car does not drip. Most likely the hoses have gone bad or the clamps have become loose.

[piper6909]

Originally Posted by vkmotorsports

Thank you all. blue62, I filled up the tank all the way, I did the pressure test on the tank as per the Bentley manual using the harbor freight kit and it did not show any sign of leaks in the tank area. At least the tank is not cracked and was still full after the pressure test.

I flipped up the bleeder valve locking clip a couple of times and there were no leaks and drips initially when I started and moved the car back and forth in my garage to driveway. I drove the car for 0.5 mile locally, and saw no leaks or drips at all. Coolant level looked full in the tank exactly as it looked when I had filled it up

Drove it for 5 miles after waiting 30 min, and making sure there were no drips or leaks.

After the 5 mile drive is when I noticed that the dripping began again in 3 different spots which coincide with hose placements most likely - 2 in the middle of the car and one near the front of the car towards the radiator.

I am waiting for the car to cool down to check the coolant level after the dripping has stopped. Most likely the hoses are failing when the car gets hot.

Then I will redo the pressure test and look for hose leaks again.

I am contemplating that in a hot condition the hoses may be expanding to cause dripping/leaking and when cold the car does not drip. Most likely the hoses have gone bad or the clamps have become loose.

From your description, I doubt the hoses are your problem. That's generally not how hoses go bad. I'd suspect your water pump. More specifically, the shaft seal.

[vkmotorsports]

Originally Posted by piper6909

From your description, I doubt the hoses are your problem. That's generally not how hoses go bad. I'd suspect your water pump. More specifically, the shaft seal.

Thank you piper6909.

1) When you say "water pump" is that the same as "coolant pump" in the Bentley manual ?

2) Is the "shaft seal" same as "crankshaft seal" ? that repair work is beyond my capability at the moment.

What would the approximate cost of repair be for this at an independent repair shop ?

[piper6909]

Wait, did I read correctly that it's leaking in the front too?

[vkmotorsports]

Originally Posted by piper6909

Wait, did I read correctly that it's leaking in the front too?

sort of. there was drips from the front body part area, and then also from the plastic shield cover area. It could just be the same leak flowing forward since my driveway slopes downward and the car nose was along that slope.

I did not take a picture but next time i will take a picture to mark the exact location. Either way I have to lift the car up fully and take out the plastic shields and examine stuff.

[piper6909]

Originally Posted by vkmotorsports

sort of. there was drips from the front body part area, and then also from the plastic shield cover area. It could just be the same leak flowing forward since my driveway slopes downward and the car nose was along that slope.

I did not take a picture but next time i will take a picture to mark the exact location. Either way I have to lift the car up fully and take out the plastic shields and examine stuff.

In that case, yes, it could very well be rolling toward the front of the car with the driveway slope. Otherwise, although highly unlikely, it could be one of the tubes running to the front of the car.

[pilot4fn]

Originally Posted by piper6909

In that case, yes, it could very well be rolling toward the front of the car with the driveway slope. Otherwise, although highly unlikely, it could be one of the tubes running to the front of the car.

I had this weekend a small leak pretty much in same location as the OP has, showing mostly at the under the front of the engine bellypan. Also a small amount of water dripped little more forward (maybe under the seats location) as I was racing at the track.
Had to retire before last two starts and took the car home driving it... while keeping cabin heater on HOT sertting and selecting only highway roads to allow coolant to stay relateively cool - I have a low temp thermostat.
No leaks on the way home for 110km and temp stayed low.

Opened the bellypan under the engine and found out the leak coming from water temperature sensor, but only when the water was at normal or higher operating temperature and the water pressure was high.

[Frodo]

Unless I've missed it, a question or two that haven't been asked: How many miles on the car when you got it? And, to your knowledge, has the WP ever been replaced (by you or the PO)? If not, it's waaaaay overdue.

[Starter986]

Originally Posted by pilot4fn

I had this weekend a small leak pretty much in same location as the OP has, showing mostly at the under the front of the engine bellypan. Also a small amount of water dripped little more forward (maybe under the seats location) as I was racing at the track.
Had to retire before last two starts and took the car home driving it... while keeping cabin heater on HOT sertting and selecting only highway roads to allow coolant to stay relateively cool - I have a low temp thermostat.
No leaks on the way home for 110km and temp stayed low.

Opened the bellypan under the engine and found out the leak coming from water temperature sensor, but only when the water was at normal or higher operating temperature and the water pressure was high.

You do know the low temp therm has absolutely nothing to do with how hot/cool your engine runs, right?

Have you considered snuging up the temp sensor?

[vkmotorsports]

Hello All,
I finally found time a month later to do this fix, as life got in the way.

I removed the belly pans/splash shield first. Did a coolant pressure test to 19PSI and actually now can see where the leak is coming from. Not sure which pipe this is but it is close to the water pump.

Looks like a T- connector connecting this hose to another hose is cracked and is the source of the leak. The pressure drops from 19PSI to 18PSI in about 5 minutes or so with the dripping.

I have attached 4 images: one from an angle from the passenger side, two from the hose that has the dripping and one that is a good picture of the full crack (red arrow).


- Cracked T-connector


- Drip from the crack


- Drip from the bottom of the hose (looks like no cracks here, just flow of coolant)


- Location of the hose from the passenger's side for context


I understand that replacing this whole hose and hose connector is needed, which will involve a full coolant flush/bleed too.

What is the interim solution ? Can I JBWeld something here ? I have a PCA meet next Saturday and would like to go for it.

Can anyone guess why the crack happened ? is it normal wear and tear or did the previous mechanic use a bad connector or something ?

Thank you in advance for advice.





Best
VK.

[Stl-986]

you really just need to get it lifted in the air, remove the pans and the pressurize the system. That is the safest method to finding the leak. Otherwise have it towed to a shop and have them find it and fix it.

If you continue to drive the car you will end up causing more damage and then will be asking what it takes to remove & replace the engine.

With coolant leaks and major oil leaks you dont want to just keep running the car to find the issue, it will be worse for your wallet.

Yes, you could have a host that is failing when hot, but pressurizing the system will show hose issues also, without the engine getting hot & overheating....which WILL happen if you continue to drive it or run the engine.