Coolant System

[Black Hole]

I am troubleshooting a potential issue with my coolant system of my 2.0L Duratec powered Caterham. Any insights would be helpful.

 

Background

- noticed drops of coolant in the engine bay but no significant loss of coolant. Visual inspection of the hoses shows no obvious leaks

- the car had 900 miles when I received it, but only about 100 miles since the engine was rebuilt

- the car has never over heated, and in fact runs very cool. I got the car October 12th and have only driven in a temperature range of mid-30s up to mid 60's. Typical coolant temps have been cold at 60 deg C, I might have seen 80C but it has never gotten hot.

- after the first time i ran the heat I had a significant drop in coolant within the overflow reservoir (a very small amount of coolant at the very bottom). I added 6-8 oz of water up to the max line (car was cool). It is possible (likely) the car had never been run with the heater so perhaps there was air in the system?

- while getting on the highway after driving the car about 1 mile from cold I had a very light mist of fluid appear on the windshield (the louvers do a nice job of directing the fluid back on the windshield).

- after another longer drive the coolant was well below the min line and I added another 6-8 oz of water (I think to the min line).

- after running I have seen the coolant as high as just below the top expansion tank hose that leads to the back of the cylinder head.

- had my buddy follow me while driving to confirm we do not see white smoke in the exhaust.

 

Car is put away for the winter so no more driving for troubleshooting as 8" of snow are now sitting outside.

 

So I am not sure I am losing significant amounts of coolant. Is it possible this is just mist released when the pressure cap opens. I don't see any scupper to capture steam/moisture when the expansion tank cap opens. It does not appear there is enough coolant in the engine compartment to explain the amount I have added. Could I still be filling air pockets in the system? Do in need to pressurize the system as I could have a pin hole leak someplace that is not easily visible. Radiator core looks dry and n droplets seen inside the shroud on the back of the radiator.

 

I attached some typical droplets seen.

 

 

Thanks

[m wirth]

Could it be that all the air is not bled out of the cooling system? my 20r Toyota motor would do several strange things until I purged all the air.

[Black Hole]

Thanks. Yes, that is one possibility that would explain the fluctuations but I am still finding the droplets in the engine bay. The droplets may just be small amounts and not actually causing the requirement to add fluid.

 

Could it be that all the air is not bled out of the cooling system? my 20r Toyota motor would do several strange things until I purged all the air.

[slomove]

Very small amounts can come from the coolant pump weep hole (a little hole in the side of the pump housing where the shaft bearing sits). A few occasional droplets may be o.k. but if large amounts come out the pump seal may be bad. I would tape a piece of paper towel to the pump and check if it is soaked after the drive.

[yellowss7]

Hi Jay, Since your expansion tank is up front, your heater may be at the highest point if its up on the scuttle. I've found a bleed tee that you can pick up at Auto Zone, installed high up in the hose that leads to the heater is the best way to ensure that the system is topped up properly.

 

Fill the system from the expansion tank then stop when it reaches the max line. open the bleed tee and fill the rest of the hose from the tee. Make sure the heater valve is open and then run the car until the thermostat opens, that should ensure that the coolant gets circulated throughout the engine. Fill up from the expansion tank if necessary to bring it back to the max line. Once cool you can open the bleed tee to ensure that there is coolant right up to that highest point. And you may want to replace the coolant cap with a new one. I found them to be about $10 at a local Jaguar dealer and they can have it in a day. Cheaper than the Ford dealer surprisingly. Good Luck Tom

[Black Hole]

Thanks. I'll take a look but the pump is low on the engine and I am seeing droplets of coolant on the valve cover and the overflow reservoir. I think it would be unlikely to get in front of and high above the water pump?

 

Unfortunately I don't live in warm CA, but in CT with 8" of snow on the ground I don't think I will get a driving test soon

 

Very small amounts can come from the coolant pump weep hole (a little hole in the side of the pump housing where the shaft bearing sits). A few occasional droplets may be o.k. but if large amounts come out the pump seal may be bad. I would tape a piece of paper towel to the pump and check if it is soaked after the drive.

[Black Hole]

Yes I do have a heater on the scuttle and thought about air being in the system. I *think* the expansion bottle is higher but there certainly may be air in the system. Good idea on the Tee fitting and filling from there. In the Caterham build manual they advise adding coolant into the upper heater hose at the location it connects to the heater valve to minimize the amount of bleeding required. I don't know what George did at Mid-Atlantic when he built the car and that is why I suspected air in the system the first time I added coolant.

 

Hi Jay, Since your expansion tank is up front, your heater may be at the highest point if its up on the scuttle. I've found a bleed tee that you can pick up at Auto Zone, installed high up in the hose that leads to the heater is the best way to ensure that the system is topped up properly.

 

Fill the system from the expansion tank then stop when it reaches the max line. open the bleed tee and fill the rest of the hose from the tee. Make sure the heater valve is open and then run the car until the thermostat opens, that should ensure that the coolant gets circulated throughout the engine. Fill up from the expansion tank if necessary to bring it back to the max line. Once cool you can open the bleed tee to ensure that there is coolant right up to that highest point. And you may want to replace the coolant cap with a new one. I found them to be about $10 at a local Jaguar dealer and they can have it in a day. Cheaper than the Ford dealer surprisingly. Good Luck Tom

[m wirth]

This is the product, Spill Free Funnel from Lisle tools, that I have used on my Toyota and my Ultralite, really worked great. there is a short video too.

http://www.lislecorp.com/divisions/products/?product=606

 

mike

[scannon]

I have one of those funnels. It works very well on Miata engines. Even with that I still have to "burp" the coolant system a couple of times to get all the air out. I use the funnel to fill, then cap the radiator and run the engine until the cooling fans cycle a couple of times then turn it off and let the engine cool to ambient. Top off the radiator and fill the overflow tank to the middle and repeat until it stops taking coolant.

 

This may be the problem you are having as whoever filled the engine after the rebuild trapped some air in the system. That would be really easy with the heater being higher than the fill tank. The previously mentioned valve in the heater hose at the high point would get the air out of the heater but not any trapped inside the engine.

 

Try a few burps and see if the problem goes away.

 

From the picture it looks like the cap on the plastic tank is the pressure cap but I don't see a line to take away any overflow. I would guess coolant is coming out when that cap reaches its pressure limit through a relief hole and spraying on the engine.

 

I didn't use the large plastic OEM coolant tank on my Miata powered Caterham. I ran a small line from the top of the hot side tank of the radiator back to a Canton pressure tank mounted just in front of the heater. Usually one burp cycle is all I need to get the air out.

 

The Canton pressure tank has a side nipple on the neck that the pressure cap fits onto. There is a line from that nipple to a catch tank mounted low on the frame. The system doesn't have an air space in the pressure tank and as the coolant heats up, expands and pressure rises to the relief pressure of the cap the excess water goes into the catch tank. As the engine cools and the water volume contracts, vacuum pulls the fluid out of the catch tank and back into the pressure tank.

 

Edited December 18, 2016 by scannon

[Black Hole]

I have never seen this, so thanks for the tip.

 

This is the product, Spill Free Funnel from Lisle tools, that I have used on my Toyota and my Ultralite, really worked great. there is a short video too.

http://www.lislecorp.com/divisions/products/?product=606

 

mike

[Black Hole]

Correct, the cap is the pressure cap. Your comment about coolant coming out of the vent hole of the pressure cap is what I am thinking may be happening. I would expect many people to see this issue on the Caterham if that is the case.

 

Here is a picture that show the upper hose from the tank to the back of the cylinder head to route coolant if the expansion tank is full.

 

http://www.usa7s.net/vb/attachment.php?attachmentid=12041&stc=1

 

Some pictures of the cap. Standard Ford cap. I did not find where the air vents from The only location I can determine is it vents from between the concentric rings outside the threaded area. The cap is ratcheting when you put it on so the outer to do this and top is separate from the area with the threads. And is the venting bringing the coolant with the pressurized air and then condensing in the compartment? Certainly the higher the level in the expansion tank the more likely it is to do this

http://www.usa7s.net/vb/attachment.php?attachmentid=12042&stc=1

http://www.usa7s.net/vb/attachment.php?attachmentid=12043&stc=1

 

From the picture it looks like the cap on the plastic tank is the pressure cap but I don't see a line to take away any overflow. I would guess coolant is coming out when that cap reaches its pressure limit through a relief hole and spraying on the engine.

 

[1turbofocus]

If you want to know if the cap is leaking then wrap some paper towel around the jug and tape it on , that will show you , You have a 16psi cap , cap could be bad if you replace the cap with another 16-18 psi and it still does it then you could have internal engine issues

 

Some pep boys have ways to test the raid cap to see if its hold psi or you can buy the tool your self

 

Tom

[Black Hole]

God idea on the paper towel wrap. I will try that once driving season starts up. I thought about just buying a new cap as that is cheap but checking it may be smarter.

 

Thank you

 

If you want to know if the cap is leaking then wrap some paper towel around the jug and tape it on , that will show you , You have a 16psi cap , cap could be bad if you replace the cap with another 16-18 psi and it still does it then you could have internal engine issues

 

Some pep boys have ways to test the raid cap to see if its hold psi or you can buy the tool your self

 

Tom

[BruceBe]

I would look at a potentially defective reservoir cap, and, make sure that you're not getting coolant temp spikes from a sticking thermostat (or other cause).

 

-Bruce

[Black Hole]

Thanks, I do not think I have any temperature spikes (at least it does not register on the gauge) but I will look at the coolant cap and likely just replace because it is so cheap.

 

 

I would look at a potentially defective reservoir cap, and, make sure that you're not getting coolant temp spikes from a sticking thermostat (or other cause).

 

-Bruce