I am back and in need of help/guidance. 2006 S type 3.0 v6, 125k miles and overheating big time.

The dash has a red light on saying coolant low, even after coolant reservoir has been topped off. Filling the reservoir turns the light off for maybe a minute of driving, light comes back on - reservoir empty again. Obviously leaking. No other codes on dash / no check engine light.

Car drives well but overheats when idling or driving slowly, at highway speeds 70+ car is cool and needle stays in the center of the temperature gauge.

Vehicle temperature gauge hit the red mark while sitting in traffic and started steaming - i shut it off asap and let it cool down. Put more water 40min later, car started and drove fine for 2miles until I parked it at home.

My first step, lift the car fill reservoir and look for leaks. Use my IR gun to check hose temp and feel for water (coolant leaked all out, will replace after leak is fixed)

Next step, not sure??
(have not changed any cooling system parts in the past 2years/25kmiles)

Appreciate any help and advice--- love this forum!!!!!

 

I was reading this post from another member:

https://www.jaguarforums.com/forum/s...t-leak-108364/

But its a bit advanced for me, I am a serious DIYer but will need step by step advice (forum members? lol) & guide (JTIS) . thanks in advance

 

Step one sounds good, let us know what you find.
Can you borrow a pressure tester from Autozone or somewhere to try and find the leak without running the engine?

 

To add, you have a major coolant leak you should be able to see. If not, then you have an internal coolant issue (head gasket)

After pressure testing the system I would pull the water pump and check the impellers.

Good luck

 

Thank you both for the replies. Have not touched the vehicle yet, ordered a pressure tester from amazon $50 ... will do that test and update in a few days. First ill dry off everything I can and once I get the vehicle under pressure I just look at all hoses etc to spot dripping water correct? Pressure to 15psi is ok for the s type?

The leak must be pretty large since I filled the vehicle with at least 2 gallons that emptied quickly. Hoping its easy to spot during the pressure test.

 

I have a 3.0L like you and have had coolant loss issue. Mine had three culprits:

1. the 'turret' on the top coolant hose broke. See picture on the left. Well known issue and the first place to check.
2. the reservoir lower nipple developed hairline crack. It leaked when pressurized. Reservoir replaced.
2. upper hose from water pump to DCCV split. This is part quality issue and remedied with better quality hose.

 

^^ Spot-on advice from TonyX. Check all of those sources carefully (especially the reservoir nipple and the turret on the top hose) before you do anything else. The weak plastic used in these parts flat-out kills them after just a few years....

 

I order the upper hose assembly without the hoses, it was a lot more to contend with. I attach my old one on to the new one by breaking the plastic that was really attached to the rubber hose. The pressure was too much so I had to get a hose clamp. I found out when I smashed the gas when driving home I lost coolant all over the road and the engine compartment. It was $40 bucks on ebay, plus the "turret" was a hexagon it was a lot better then the oem style. Don/t forget to burp the air out that was most of my over heating issue. My gauge was reading different it raised quickly then cool down quickly. My Cylinder head temperature was not picking up the coolant it was empty.

 

Quick update. Filled reservoir with 1.5 gallons of water and pressure tested. No drips or water found under the car. I tested at night so will replace the reservoir for now and retest. To confirm I am buying the right part - ebay reservoir w/cap $33

pumped to 15 psi and pressure dropped to less than 7 psi in under a minute. I found a pressure leak in the reservoir tank along the top seam, where the black plastic meets the clear plastic - also found my reservoir cap is not sealing well. Even while pressure testing I did not see water dripping, but i did hear air escaping - I still cant understand how the vehicle loses 2 gallons of water with a small air leak?


Thank you TonyX for the insight, will check those spots asap.

 

Quick update - vehicle has not been turned on in 3 days. Noticed water leaking from the exhaust pipes. See photo ... will check more into later tonight. Im scared - possible head gasket? Would water be leaking even when the vehicle is off?

 

Please forgive if my question strays too far from this thread. I'm replacing coolant reservoir/overflow tank. Received new one in the mail, but there is a part rattling inside where the coolant level probe electrical connection affixes to the tank. Is this normal? Should I send it back? Thanks.

 

Yes, normal

 

Yes, could be condensation..

 

cUpdate - inside the exhaust pipes seems dry for the moment, no water on the floor/pipes. Also, oil dip stick is clean and so is oil cap - no sign of water there. Reservoir is still full from the other day that I filled it. Will pressure test again once new reservoir is in. At that point will test turn vehicle on and check exhaust when its at temperature. Unless I hear other thoughts I should do this sunday.

Thanks again.

 

If you have corrected all the leaks and replaced the hoses, you may want to consider the water pump being the issue. If the pump is rotating but the impeller has come loose from the shaft, the engine can overheat.

 

In addition, how old is the thermostat? They are generally serviceable for three to five years.

Be sure to replace the thermostat with one that is to OEM specification as aftermarket ones sometimes do not function correctly.

 

It took me awhile to diagnose partially clogged radiator (50/50), I used "laser" thermometer.
Another unusual, I think, problem was rusted water pump impeller. Previous owner had water in cooling system and impeller rusted and fell apart.
I suggest buying "laser" thermometer from Harbor Freight ($25)
`http://www.harborfreight.com/catalogsearch/result?q=infrared+thermometer`

 

Thanks abonano. I'll be installing the coolant overflow tank tomorrow.

 

Update - changed the coolant reservoir , added 1 gallon or so of water. Pressure tested at 15-16psi car held that pressure for 5-10min with no leaking of air or water.

Both exhaust pipes were dry, turned on car, opened the reservoir cap and noticed the water moving- let it sit for 5min, no water leaking- temp got up to normal , right in the middle of the gauge (fan never turned on) - took the car for a 5 min drive. Temp stayed at middle of gauge. Parked car, no leaking water, temp was still at middle of gauge, let car sit for 1-2min , fan still was not on.

Both exhaust pipes had water in them, enough water in each to fill the pipe almost the to lip and I think it would keep filling and spill out if I kept testing. So I am guessing this is where my water has been leaking from but I never noticed it before?? Pretty sure the car did not overheat because the water was still circulating and did not leak out yet.

Would a stuck thermostat/broken water pump cause that symptom? Is moving water in the reservoir telling me pump is ok? Neither of them have been replaced in the past 2 years, history before that is unknown.


Help & thanks again , no clue what my next step is. Best guess is it ok to drive the vehicle temporarily until this problem is fixed?

 

The water in the exhaust is condensation from the combustion process. It's normal.