I have a 1999 Supercharged Vanden Plas that loses coolant only when running the heater. We've put new bleeder hoses everywhere, (except to the overflow), replaced the thermostat, the bypass hose from the thermostat to the coolant inlet, and replaced the expansion tank cap. They all had minor leaks and the bypass hose looked like a balloon about to bust. We've looked everywhere for the leak and practically climbed in there tracing the octopus hose, checked all around the expansion tank, the overflow tank, got under it with it running and right after turning it off, started it up and looked for steam at night with a bright light, and just can't find it. We can't smell burning coolant since fixing the leaks. It just loses about a half inch of coolant each time you drive it with the heater on. If you don't turn on the heater, it doesn't lose coolant. Also, you don't smell anything funny from the heater when it's on. If anyone has any clue as to what it could be please let me know. Thanks

 

If the windows are fogging up with the heater on, your core has a leak. Any dampness on the carpets?

Any coolant under the supercharger? Maybe one of those two hoses that run under the intake manifold.

 

Suggest getting a cooling system pressure tester. Being able to over-pressurise can identify leaks fast. Cranked my Land Rover V8 up to 25 PSI, and found 4 leaks right away.

 

Thanks for the suggestions. We considered the hoses under the supercharger, but there isn't a smell of burning coolant anywhere in the engine compartment since fixing the leaks we found. I have watched all around it with the car running and after it was shut off, in the daylight and with a bright light at night, no hint of steam or a smell. Could it still be those hoses?
There has never been a smell in the cabin. I pressed white paper towels into the carpet and found no moisture, although it kinda feels like there might be to your hand. The windows don't fog up, but one time, a couple of weeks ago, they did, but we were running the defrost at a colder temp than the outside air, when I turned the temp up, it cleared.
I'm trying to find someone to do a pressure check on it, but nobody wants to touch it. We live in the boonies, the closest Jaguar dealer is about 150 miles away, and the closest foreign car mechanic is a hour away, and extremely expensive. We may have to buy the stuff to do it ourselves.
Just to be sure, the coolant, when checked cold, should be touching the bottom of the neck?
One other observation, the white overflow tank has some coolant in it, maybe 1 to 1 1/2 inches up the side. I can hear and see coolant go in there if checked without enough time to cool, and when I checked this morning, (completely cold), I could hear like two little drops fall into the coolant. Shouldn't it draw that back up into the expansion tank if it needed it? And should I be able to hear it drip in there? The hose seems to be pushed all the way in, there's a bend in the hose that won't allow it to go further down.
Any and all suggestions are appreciated, we are at a complete loss. I think my husband is sometimes about ready to chop Kitty into itty bitty pieces. This is his dream car and he hasn't been able to enjoy it.
Thanks again.

 

If one of the two heater hoses under the supercharger is leaking this does not necessarily lead to a smell of burning coolant. The coolant will sit right in the middle of the "V" of the enginge (between the two cylinder heads, see red tagged area in attachmed picture) and will not be burned. When (hard) accelerating or when it's too much coolant there, it will stream backwards over the sides of the transmission bell housing. So if you find any coolant residues or traces there, that would be pointing to leaking heater hoses under the supercharger.
Cheers, Alexander

 

Thanks xjr2014_de,

Question 1: Could this happen only when running the heater?

Question 2: Could this cause a drip onto the spark plugs? Because now there is a little roughness on startup, and the restricted performance light and CEL are on.

 

First off, I think he might be overfilling it. He needs to leave the cap off the overflow tank, turn the heater on and run it up to temperature, letting all the air out of the system (including heater). Top it off, about an inch below the filler neck (below the overflow hose that runs to the tank in the wheel well). Be sure those overflow hoses are routed correctly -- the outboard nipple goes to the radiator, the inboard to overflow tank in the left wheel well (opposite to what would seem the obvious routing).

He needs to buy a good OBD II reader and read the fault codes to find what is causing the rough running and check engine light. Then search the internet for suggestions on what those fault codes mean (P1111 is the only good code!) or come on back for free advice (for what it might be worth!).

Some obvious questions: have the secondary tensioners been replaced with modern metal ones? New water pump along with the new TST? Mileage? What has been done since it last ran well?

 

Thanks Jhartz,
I was wondering if we were over doing it on the coolant. We had read somewhere that you fill it to the bottom of the neck. Wrong, obviously. The hoses are routed correctly, one of the first things we checked.

We've only owned this one about 6 weeks. We drove 8 hours to South Florida to pick it up from the original owners wife. An hour from home the low coolant light came on. It was the middle of the night, so we added a small amount of bottled water. We didn't have anymore trouble for about 8 or 9 days. Then low coolant again. We found a couple of leaks from the tank hoses, and the one going from the tank to the thermostat just snapped.

We have replaced all those small hoses, (except the one going to the overflow), The big bypass hose from the thermostat to the inlet, the thermostat, and the expansion tank cap.

Unfortunately, we don't know if they had the water pump or the tensioners replaced, we haven't. It has 99,000 miles on it.

We will definitely follow your advice and bleed the system. Then I'll see if I can get the codes read. We've gotten tons of good advice on here and we definitely appreciate it all.

 

Good evening to everybody,
1.) Since the two hoses under the supercharger are heater intake and outlet pipe - potentially yes. Otherwise the whole system is under pressure and there's no valve involved at the thermostat when turning on the heater. And since the outlet pipe is joined together (via a t-piece) with the coolant line coming from throttle body and egr valve (if fitted), the leak should be found at the heater intake side and/or the heater block and/or air conditioning evaporator if the leak situation can be related doubtlessly to turning on the heater.
2.) No - there are no coolant lines above the spark plugs (except if the coolant lines of the charge aircoolers are leaking which you would definitely see). Just remove the coil covers and disconnect the coil packs so that you can take a look into the spark plug wells if they're soaked/flooded.

Since you replaced all the small hoses, did you ever get the "low coolant" notification again?

Cheers, Alexander

Cheers, Alexander

 

Hi,
No, we haven't gotten a low coolant warning since replacing the hoses. To tell the truth, we have obsessively checked it since then, (we can both be a little OCD). I think we were overfilling it, per Jhartz post. We're trying to confirm definitively that it doesn't leak when not running the heater. He drove it 40 miles last night without the heater. Then when I checked this morning it was about an inch below the filler neck. So I drove it about 25 miles today without refilling it and without the heater. I'll check it after the 6 hour cool off period. If there isn't any loss, we'll drive it again with the heater on to make sure we're still losing coolant. I suspect we are, though, because last time we ran the heater the tank was only 1/2 full when checked. If we are, I guess we'll be learning how to remove the supercharger next.

I had the codes read at the parts store today: P0302 -cylinder 2 misfire, (5 times), P1316 - excessive emissions bank 2, and the P1111 code. So, I'll be researching that. I've smelled gas in the engine compartment on the right side since a little mishap connecting the battery a few days ago. The car started and ran for about 5 seconds, then cut off with a "battery not charging" warning. Tightened the neg. cable and it started fine. However, we had gotten the restricted performance light twice before, though, after using the cruise control, (connected?). We were going to tackle the throttle body after the coolant system. When I asked the parts guy if they could be connected in any way, he mentioned the dreaded head gasket. Which is beyond our meager capabilities, I'm sure! So, praying it isn't that. Any thoughts on that? We'll check on the spark plugs as soon as we can, time and weather permitting.

Thanks

 

Hi,

Coolant loss: I'd suggest to check the coolant level before taking the cat to a ride with heater on and watch if the "low coolant" notification pops up again (don't forget to take coolant for possible refill with you ).
Once I also had this notification on the autobahn and refilling was no problem (after a couple of minutes of cooling down) - in the end I had leaking bleed line.

Codes: Because of the codes, I'd reset them and watch if the CEL is coming back. P1316 flags only when a misfire code (in your case it's P0302) pops up as well.But as you mentioned before, the mishap with the battery could have led to this.
But P0302 does not point to cylinder 5 which is misfiring...it's cylinder 3 (see attached engine_dtc.pdf and picture). Codes P0301-P0304 relate to bank 1=bank A (right bank of engine when sitting in the car, counting from front to rear of the engine) and codes P0305-0308 relate to bank 2=bank B.

Restricted performance: If the "restricted performance" alert is related to the cruise control the most likely root cause is the brake pedal switch. Probably it's broken, misaligned or the micro switches inside are on their way out. Just check the forum, there are plenty of threads on that issue.

Head gasket: I do not think that the head gasket can be related to the loss of coolant when turning the heater on. If the head gasket is failing, you'd loosing or burning coolant as soon as the engine is running. Excessive white smoke out of the exhaust system might be a signal for burning coolant. In my opinion, that's a very unlikely cause for your coolant issue (provided that it is still an issue *gg*)

Best regards, Alexander

 

There is a heater bypass hose/circuit might alleviate
pressure on the hoses and joints closer to the heater
when the heater is off. So maybe the hoses and joints
after the bypass?

Auxillary heater pump? It might only be under pressure
when heater is on.

 

Thanks for the info, suggestions, and definitely the diagram.

We may be back at square one. When I checked it late last night, it had lost coolant, even without running the heater. The tank is half full.

I made two observations:

1. The threads around the cap were wet. They definitely were not when the cap went on. The cap is also hard to get off. I had to use pliers to open it.

2. The overflow in the wheel well has less in it than before, maybe 1/4 to 1/2 inch up the side, not counting the depression on the bottom. So, I assume, (rarely a good idea!), that it drew some from there when it needed it.

I did not get a low coolant light when driving it. Why not? Am I losing it as it cools? Or does it just still have enough to register because it's moving around while running?

I don't think I've mentioned that it has never shown hot, (for us). I know it's an idiot gauge, but it just barely touches the center line, has never even sat directly over it.

Should I buy another new cap? Or a whole new tank? If I buy a new tank do I need the level sensor, also?

I'm also going to go ahead and order the hoses under the supercharger. Is there a gasket under there that I need to order? I know I've seen instructions on here on how to remove it, so I'll look that up.


We're having really bad weather today, so I doubt I'll get the chance to do anything, other than order parts.

Thanks, again

 

A couple of observations:

I did not notice anyone suggesting checking the reservoir tank neck hoses. They get mis-connected frequently because the correct arrangement looks "wrong'. The hoses should cross each other at the tank. i.e. the hose going to the overflow tank should be the upper one on the neck. Cross connection could match your symptoms, except for the "happens only when the heater is on" report. Pictures are in the archives.

You did not acknowledge the suggestion from Alexander about the brake pedal switch causing Restricted Performance. That is a little counter- intuitive, but is a known issue on these cars. The diagnostic differentiation is your observation that it happens after using cruise control.

 

+1 on what sparkenzap said!

As I was thinking around corners - what if there are still air bubbles inside the system?! Since you had issues with various leaks it's conceivable that air had been drawn in when the cooling system was cooling down. Especially when your bleed lines (from and to the header tank) were leaking as well. In this case the air would be trapped somewhere (e.g. heater system?) and cycled around and from time to time finally some air will get to the header tank where it's supposed to be. And this could be misinterpreted as "loss of coolant". Did you follow the procedure of filling the cooling system as mentioned in JTIS? As the cooling system of our supercharged vehicles is much more complex and involves more parts than for the normal aspirated cars, the correct filling process is essential. There had been a thread where an user reported about various intermittent weird symptoms because of air in the cooling system.

 

We ain't reading everything. It was suggested that the overflow hoses might be misconnected #7: they reported they are correct. After all this time, the air has got be gone! Even for a blown unit.

Sounds more and more like a head gasket! Any white smoke? Any foam in the oil?

I would still be concerned not knowing the status of the tensioners.

I can't find my charts for numbering cylinders, but I think #11 is wrong: number two hole is second back on the right side. That coil needs to be cleaned and spark plug pulled and checked.

Would be useful to hear if the RP still occurs with the cruise control switched on (does the cruise control work?). Brake switch, as noted, is a frequent cause, not expensive, but a PIA to repair (unless you are under five feet and have small hands).

 

Jim:
I see the crossed hose suggestion and acknowledgment now- I missed that! So, I agree that the head gasket needs to be strongly considered.

And, I agree, the previous picture in #11 is the "new" way that some Jag engines are numbered. An AJ26 or AJ27 engine is "pre 2002.5". as shown on the left side of this picture. Even this picture is slightly misleading in that it has an arrow at the front of the engine, pointing rearward, that says "Front of Engine".

 

Hi, We've had bad weather today and I have internet via satellite, so I haven't had a signal most of the day. Sorry for not getting back sooner.

Plums, if your talking about the hoses in the back of the engine compartment, near the firewall, we've observed them for a long time while running the heater. I practically crawled in there with a flash light and mirror and couldn't see any leaks. I did however get my hands stuck several times. I'm sure it looked hilarious, a fifty year old red head sprawled all over the top of a jag engine! Luckily, we don't have any close neighbors. The pump also seems to be working. Unless it's where the hoses, (pipes?) go into the firewall or past that, to the core. But there isn't a smell in the cabin. It does seem to the hand that the carpet is damp, but I pressed white paper towels down all over and couldn't find any moisture.

We'll definitely check out the brake pedal switch. The cruise does work. It hasn't happened to me, I'm too much of a control freak for cruise control. It had only happened a few times, but seemed to fix itself. It seemed to work okay the last time, but the next day the RP came on again right after putting it in gear. Before that it happened after he used the cruise for about 40 minutes or so. So, I'm not positive it's connected but seems to be.

The oil looks good, but could use a change, no foam. And there isn't any oil in the coolant. There is white, what seems more like steam. There doesn't seem to be any smell to it. It's about 50* here during the day. It was warmer yesterday when I drove it and I didn't notice any smoke or steam. I had a brace for the muffler welded back on and I watched them drive it over to the bay. I probably would have noticed it. I've seen several people on here go through all this and end up with a blown head gasket, I hope we don't join the ranks.

He's going to pull the spark plug and clean the coil Friday. I ordered another new cap for the expansion tank, it'll be here then, too.

About the tensioners, would it matter if it was an AJ26 or AJ27 engine? How could I find out, if it matters? What we were told was that they actually bought the car in 2000, but because they didn't like the changes to the body in the 2000 model, they got the 1999. She said they special ordered it with the supercharger, (and an analog clock). I have to cross reference every thing between the Vanden Plas and the XJR, because neither Jaguar, nor anyone else, lists a 1999 Vanden Plas Supercharged. The dealer even gave me incorrect part #'s for the hoses. I finally called John at Welsh Ent. and told him what #s I thought and what the dealer said and got the right ones from them. So, after all that, is it possible Jaguar took care of the tensioners or that it already had better ones? There doesn't seem to be any bad sounds coming from it.

We didn't remove the plug from the charge air cooler. So, no we didn't follow the directions. At the time this seemed like a simple hose replacement. Plain ole air in the system would be great. Do you all think we should go back and do it again?

Thanks to everyone for the help.

 

So, the cylinder we're looking at is the 2nd one, from say the head light, on the right side of the car, correct?
Thanks for the update.

 

YES... for sure!