More problems... Low coolant dummy light
#21
![Default](/forum/images/icons/icon1.gif)
if it's the hose under the bottom of the supercharger, the coolant will be on the backside of the engine and on the belly pan.
Last night I pressure tested the car and I found a pinhole within minutes. The hole is on the S shaped line that wraps around the coolant expansion tank and then goes near the snout of the blower. I'm not sure but I think it attaches to the thermostat or something else toward the middle of the engine, toward the top. It should be easy to replace.
The part was AJ811771. I did a quick glance over the net but ended up ordering from the local dealer. The cost out the door was $86. Fortunately, it looks like an easy repair.
By the way, I also used the harbor freight radiator pressure testing kit. It comes with tons of differnt caps to fit just about all applications. It cost $100 but I had a 20% off coupon.
Last night I pressure tested the car and I found a pinhole within minutes. The hole is on the S shaped line that wraps around the coolant expansion tank and then goes near the snout of the blower. I'm not sure but I think it attaches to the thermostat or something else toward the middle of the engine, toward the top. It should be easy to replace.
The part was AJ811771. I did a quick glance over the net but ended up ordering from the local dealer. The cost out the door was $86. Fortunately, it looks like an easy repair.
By the way, I also used the harbor freight radiator pressure testing kit. It comes with tons of differnt caps to fit just about all applications. It cost $100 but I had a 20% off coupon.
#24
![Default](/forum/images/icons/icon1.gif)
As I mentioned earlier, I also experienced a coolant leak early this week. Upon further inspection it turns out it was the hose that goes from the T-Stat to the water pump as shown by the hose connection diagram below
![](https://www.jaguarforums.com/forum/members/dimension247-49654-albums-t-stat-water-pump-hose-2984-picture-pipe-connections-9051.jpg)
fig 1
These are the pictures of the actual hose that I removed.
![](https://www.jaguarforums.com/forum/members/dimension247-49654-albums-t-stat-water-pump-hose-2984-picture-pinhole-9052.jpg)
fig 2. Pinhole
If you look closely in fig 2 above you'll notice the over-sized pinhole that was result of the imminent rupture.
![](https://www.jaguarforums.com/forum/members/dimension247-49654-albums-t-stat-water-pump-hose-2984-picture-micro-cracks-9053.jpg)
fig 3. Micro cracks inside
![](https://www.jaguarforums.com/forum/members/dimension247-49654-albums-t-stat-water-pump-hose-2984-picture-weakened-reinforcement-9055.jpg)
fig 4. Weakened reinforcement
As seen in fig 3 the hose had a lot of micro cracks inside the tube to a point that it had weakened the hose reinforcement as a result it had become very soft fig 4.
About a year ago tbird6 posted some research that had been done by Gates, a belts hose and hydrolic equipment manufacturer.
Article
To summarize, they basically attributed the hose failure to a phenomenon known as electrochemical degradation. It occurs because the hose, liquid coolant (ethylene glycol antifreeze and water), and the engine/radiator fittings form a galvanic cell or "battery". This chemical reaction causes micro cracks in the hose tube (see fig 3), allowing the coolant to attack and weaken the hose reinforcement. Accelerated by high-heat and flexing, the hose can develop a pinhole leak or rupture under normal pressure.
This is exactly what happened to the hose that I removed and possibly the cause for most hose that we're experiencing.
BTW this hose was $25 from the dealer and didnt take long to replace.
![](https://www.jaguarforums.com/forum/members/dimension247-49654-albums-t-stat-water-pump-hose-2984-picture-pipe-connections-9051.jpg)
fig 1
These are the pictures of the actual hose that I removed.
![](https://www.jaguarforums.com/forum/members/dimension247-49654-albums-t-stat-water-pump-hose-2984-picture-pinhole-9052.jpg)
fig 2. Pinhole
If you look closely in fig 2 above you'll notice the over-sized pinhole that was result of the imminent rupture.
![](https://www.jaguarforums.com/forum/members/dimension247-49654-albums-t-stat-water-pump-hose-2984-picture-micro-cracks-9053.jpg)
fig 3. Micro cracks inside
![](https://www.jaguarforums.com/forum/members/dimension247-49654-albums-t-stat-water-pump-hose-2984-picture-weakened-reinforcement-9055.jpg)
fig 4. Weakened reinforcement
As seen in fig 3 the hose had a lot of micro cracks inside the tube to a point that it had weakened the hose reinforcement as a result it had become very soft fig 4.
About a year ago tbird6 posted some research that had been done by Gates, a belts hose and hydrolic equipment manufacturer.
Article
To summarize, they basically attributed the hose failure to a phenomenon known as electrochemical degradation. It occurs because the hose, liquid coolant (ethylene glycol antifreeze and water), and the engine/radiator fittings form a galvanic cell or "battery". This chemical reaction causes micro cracks in the hose tube (see fig 3), allowing the coolant to attack and weaken the hose reinforcement. Accelerated by high-heat and flexing, the hose can develop a pinhole leak or rupture under normal pressure.
This is exactly what happened to the hose that I removed and possibly the cause for most hose that we're experiencing.
BTW this hose was $25 from the dealer and didnt take long to replace.
#25
![Default](/forum/images/icons/icon1.gif)
mine was hose #3 in the diagram above. Due to the shape of it, it was expensive. When I asked the dealer approximately how long they'd bill me to replace it, they said 1 hour. Good thing I did it because it was an easy repair that was done in the dark with a flashlight in less than 10 minutes. The car is back up and running!
#26
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