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Car is stored presently, but started it last week, got distracted, and it overheated, then dropped all its coolant. There’s a hose going to thermostat housing, then going down from there…I cannot lift the car to be sure, but it feels like it has popped off. Where does it go to? What is it connected to? It would cause all cool and to drop to floor? Is it just a 1/2” or 5/8” hose or something fitted? I’ll be able to get at it in a couple weeks, can’t get pics cuz it’s wedged in tight spot, but making plans now. Was originally fitted with Strombergs, but converted to SU by previous owners. Is 1970 series 2, 4.2 convertible.
You are just going to have to lift the car and look closely where the leak is coming from then reattach. The length and shape of the hose should give you a clue. So many hoses on the 4.2 it’s like looking at a bowl of spaghetti. 😊
Was hoping to get ahead of it and have a spare hose in hand in case needed.
Coolant was spraying out under some pressure when I got to it to shut car down…I’d wasn’t just draining.
Am also hoping someone might know what it is supposed to be attached to.
Update…. My son just came in saying he crawled under and felt around….it is disconnected, but didn’t feel a clamp around loose end,
but a zip tie. Also that it appeared to come down from above ( thermostat housing, and turn back…not to radiator.
thanx for all replies.
Could the hose possibly go to the overflow tank on the firewall? You might have to refill the system with plain water and see where it is leaking maybe with motor off or motor on if the leak is past the thermostat. One reason I like the Moss paper catalog is that it diagrams every part. The hose kit is 16 different hoses…
Thanx for the diagram. No, the one to overflow res is #47, and is in place on my car. The hose I’m asking about is not shown here. I’ve looked at dozens of pics and drawings and have yet to find it. I did see a post about an air bleeding hose somewhere, but it was vague…. The post was about filling the cooling system, not specific enough. Mine goes down from thermostat, then torts back, under engine, on opposite side ….passenger,right, side. Overflow is on left,driver side.
There also appears to be a metal tank or something under carbs, towards back of engine that I have no idea what it is….. my thermostat hose may go to it?
sorry for being vague….car is in storage and wedged in pretty tight….. I can barely squeeze in, let alone bend my aging self to get at much. Suppose I’m just going to have to wait till owners of other cars return from sunny south. Thanx.
I should mention, previous owner did resto himself, but sadly passed about 6 months ago. So now I have to guess at a lot. Am more driver than mechanic too, but I try
i know it was converted to SU carbs and have a vague memory that that plays into cooling system somehow.
Car is stored presently, but started it last week, got distracted, and it overheated, then dropped all its coolant. There’s a hose going to thermostat housing, then going down from there…I cannot lift the car to be sure, but it feels like it has popped off. Where does it go to? What is it connected to? It would cause all cool and to drop to floor? Is it just a 1/2” or 5/8” hose or something fitted? I’ll be able to get at it in a couple weeks, can’t get pics cuz it’s wedged in tight spot, but making plans now. Was originally fitted with Strombergs, but converted to SU by previous owners. Is 1970 series 2, 4.2 convertible.
For goodness sakes. You are talking about the bypass hose, #29 in that diagram. It's a small curved hose that goes from the thermostat housing to a fitting on the water pump inlet. If it's broken, you will lose every drop of coolant. Order a new one from any of the usuals, or you can substitute Gates 21746 (although you're unlikely to find it locally).
The tank at the back of the manifold is the reservac, for the brake system. It's for the vacuum reserve, don't be plumbing coolant into it.
For goodness sakes. You are talking about the bypass hose, #29 in that diagram. It's a small curved hose that goes from the thermostat housing to a fitting on the water pump inlet. If it's broken, you will lose every drop of coolant. Order a new one from any of the usuals, or you can substitute Gates 21746 (although you're unlikely to find it locally).
The tank at the back of the manifold is the reservac, for the brake system. It's for the vacuum reserve, don't be plumbing coolant into it.
Afraid it’s not that part. Hose is 1/2”, maybe 5/8, goes straight down from down facing fitting at thermostat , then seems to turn aft to whatever it attaches to.
I will try to get a pic today….reportedly a couple cars have come out of the garage it’s stored in, so may have more wiggle room now. Thanks
That's the correct part. The diagram seems to have been pieced together without an eye to scale. I think the water pump in the drawing is for an S1 4.2, if you notice the diagram has two water pumps. The bypass hose (C26853) is about 5/8" diameter, and connects to the top fitting on the water pump inlet. It's a crowded area, tough to visualize and tough to get a tool in there to tighten a clamp.
[QUOTE=mpawelek;2909456]If you cannot find the hose in the diagrams maybe the previous owner modified something. Are you sure this is a 4.2 engine and not a 3.8?[/QUOTE
Yes is 4.2…. Possible it has been modified. Was originally fitted with Strombergs..he changed to SU….. I have a vague memory that he talked about ‘other things’ that had changed due to car swap.
Gonn go try getting a pic. Very tight in its storage spot.
If you cannot find the hose in the diagrams maybe the previous owner modified something. Are you sure this is a 4.2 engine and not a 3.8?[/QUOTE
Yes is 4.2…. Possible it has been modified. Was originally fitted with Strombergs..he changed to SU….. I have a vague memory that he talked about ‘other things’ that had changed due to car swap.
Gonn go try getting a pic. Very tight in its storage spot.
The Series 2 cars are poorly represented in the parts books. The diagram above is from a parts supplier website, and is cobbled together from various diagrams. It has glaring errors and omissions. For example, two water pumps, no heater return plumbing, and S1 belt and pulley system, without provision for the high mounted alternator. It shows both S2 and S3 fan motors, and the adpaters for installing the S3 fans. So don't expect your car to match the diagram.
If the car was converted to triple SU's, then the plumbing for the secondary manifold would be absent, and the heater return plumbing would be somewhat different. The thermostat plumbing would depend on whether they used a 3.8 or 4.2 intake manifold, and whether they retained the thermostat extension housing. So photos needed.
The Series 2 cars are poorly represented in the parts books. The diagram above is from a parts supplier website, and is cobbled together from various diagrams. It has glaring errors and omissions. For example, two water pumps, no heater return plumbing, and S1 belt and pulley system, without provision for the high mounted alternator. It shows both S2 and S3 fan motors, and the adpaters for installing the S3 fans. So don't expect your car to match the diagram.
If the car was converted to triple SU's, then the plumbing for the secondary manifold would be absent, and the heater return plumbing would be somewhat different. The thermostat plumbing would depend on whether they used a 3.8 or 4.2 intake manifold, and whether they retained the thermostat extension housing. So photos needed.[/QUOTE
This may explain a lot.
The hose “made in USA” goes straight down , tho it might appear in this pic that its a short 90 to manifold . that’s the one im worried may be split ( i think its just off its fitting ) and that it might be more specific than just a length of 1/2” or 5/8. I know…. i may just be refitting whats there to what it may have popped off, but our season is short here and i want to be prepared, not waiting weeks for a part. thanx for your help. most appreciated.
The Series 2 cars are poorly represented in the parts books. The diagram above is from a parts supplier website, and is cobbled together from various diagrams. It has glaring errors and omissions. For example, two water pumps, no heater return plumbing, and S1 belt and pulley system, without provision for the high mounted alternator. It shows both S2 and S3 fan motors, and the adpaters for installing the S3 fans. So don't expect your car to match the diagram.
If the car was converted to triple SU's, then the plumbing for the secondary manifold would be absent, and the heater return plumbing would be somewhat different. The thermostat plumbing would depend on whether they used a 3.8 or 4.2 intake manifold, and whether they retained the thermostat extension housing. So photos needed.
I agree the diagrams in the paper Moss catalog are not perfect and some show 1.5 and 2.0 parts on the same page but where else are those of us that are new to the E Type supposed to go for identification? The large repair manual just shows individual parts. Is there a book/source for large diagrams? I have 8 books on the E Type and none show whole systems.
I understand it's difficult currently for you to access your E. Here are two photos from my 69. He has all his originally-sited bits and pieces and I am very sure that his 'plumbing' is as it should be.
Photo 1 shows the short piece of rubber hose that connects with an 'aluminum' colored pipe that goes down, then bends back towards the firewall and connects at the back of the original air plenum that the Strombergs are connected to.
The second photo shows that 'aluminum' pipe connecting to the back of the plenum. I think this is all part of the 'breather system' and should have nothing to do with all the coolant coming out of your car. Most likely it is that lower radiator hose that has either split or the hose clamp was not on correctly and/or tight enough.
Here is a link to that 'system' and the comment that an owner disconnected it and let it drain to a catch can. The piece of hose that you felt the end of may be this. It's similar to the short piece of hose that I have connected to the bottom of my battery tray that thinks it will let water out of the battery tray.
I understand it's difficult currently for you to access your E. Here are two photos from my 69. He has all his originally-sited bits and pieces and I am very sure that his 'plumbing' is as it should be.
Photo 1 shows the short piece of rubber hose that connects with an 'aluminum' colored pipe that goes down, then bends back towards the firewall and connects at the back of the original air plenum that the Strombergs are connected to.
The second photo shows that 'aluminum' pipe connecting to the back of the plenum. I think this is all part of the 'breather system' and should have nothing to do with all the coolant coming out of your car. Most likely it is that lower radiator hose that has either split or the hose clamp was not on correctly and/or tight enough.
Here is a link to that 'system' and the comment that an owner disconnected it and let it drain to a catch can. The piece of hose that you felt the end of may be this. It's similar to the short piece of hose that I have connected to the bottom of my battery tray that thinks it will let water out of the battery tray.
Thanx for this.
This is the first, of many viewed, that shows the same fitting on thermostat that matches mine.
However, the water line coming out of it (going into?) has no metal section or piping at all. It is all rubber, can see about a foot of it as it goes down to lower level of engine, then I can only feel rubber from under the car.
Valerie, u put some time into your reply, for which I am very grateful. But I think I got something different going on. It did not seem like a breather what with system drained, under pressure, to ground. Unless, of course, I got 2 things that have come apart.
Guess I’m just going to have to wait till I can pull it out and lift it….hopefully next weekend.
Cheers.
Your photo with the made in the usa hose IS the breather. That is the top end of an XK engine and the overhead cams are right behind that round, domed fitting. There is NO way coolant came out of that made in usa hose. That is NOT the thermostat housing.
Here is a photo of what I am talking about
This is your engine. That long Made in the USA hose just hangs down. The previous owner didn't know what to do with that breather circuit as you probably don't have the connection on that triangular air filter plenum, since the carbs were switched out. There aren't any metal pipes like what are in my car, because that whole breather circuit has been cobbled.
In the second photo, your Made in the USA connection is circled in red. The thermostat and its housing are in blue.
No sense to worry about a worry until you are able to get the car in a good spot to work on it. You will resolve this!
Last edited by Valerie Stabenow; Apr 4, 2026 at 04:42 PM.
Your photo with the made in the usa hose IS the breather. That is the top end of an XK engine and the overhead cams are right behind that round, domed fitting. There is NO way coolant came out of that made in usa hose. That is NOT the thermostat housing.
Here is a photo of what I am talking about
This is your engine. That long Made in the USA hose just hangs down. The previous owner didn't know what to do with that breather circuit as you probably don't have the connection on that triangular air filter plenum, since the carbs were switched out. There aren't any metal pipes like what are in my car, because that whole breather circuit has been cobbled.
In the second photo, your Made in the USA connection is circled in red. The thermostat and its housing are in blue.
No sense to worry about a worry until you are able to get the car in a good spot to work on it. You will resolve this!
So, just cuz we’re at it, if I don’t find an obvious spot for that USA hose to connect, just leave it hanging?
…them, presumably, look for the hose or whatever that actually dropped the coolant I guess.
sorry to go on about this. I live in the middle of butt- squat nowhere…. Turn a guy into a planner ….everything takes twice as long to sort,order,receive….. and far north enough to have a short season too. I gotta get as much sorted at least in my head…..snow leaves late, comes early!
Thanx so much for your attention ( to this matter)…. Hehe.
While I've had my E for over 30 years and he has taught me a lot, I don't always fully understand these systems, it's like the PCV Positive crankcase ventilation in 'modern cars. I'm hoping someone else above my paygrade on this forum can step in to say yes to no to your question about leaving the hose hang.
No apologies necessary... I'm in central Wisconsin and about this time of year a bit stir crazy with nothing really able to do outside, inside projects all built/repaired/installed.
Yes, once you get the car where you can really see over, under and around, you will find the source. It would most likely be a split radiator hose.. one of the big fat ones. If the rubber hoses that are part of the cooling system weren't replaced recently, like in the last 5 years, or you don't know when, good idea to buy the set and replace them. Sets are available from the usuals and here's a link to a forum posting about current vendors. Be sure to compare sets as to what all they include, some may be cheaper, but they may not include all the hoses the more expensive set does.
This vendor is top notch, MORE than knows his stuff and has designed many things for our E types. I bought one of his radiators as well as his upgraded fan motors, and one of his electronic voltage regulators for the fuel and temp gauges. He's a regular contributor on that JagLovers forum.
Last edited by Valerie Stabenow; Apr 4, 2026 at 11:06 PM.
The "Made in USA" hose is connected to the crankcase vent. It should join an aluminum pipe that runs over the rail and that is joined with another rubber hose to a fitting on the back of the triangular air cleaner. IF it just hangs, then crankcase gases are just vented out to the air, like an old fashioned draft tube. It's very polluting, and it will stink up the cabin if there are any air leaks in the firewall.
E-type s2 hose to thermostat
