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Hello everybody
I have searched the forum for an answer to this, and I have seen plenty of messages refering to the V12 engine but very few about the AJ16 straight six engine, the one I have.
I am well aware that modern gauges do not show the reality but what people feel comfortable seeing (gauge needle just in the middle), but for my own peace of mind I want to ask you if the oil pressure and temperature readings of my car are what they are supposed to be.
The oil pressure needle usually stays in the position that the picture is showing, and sometimes it goes a little higher, just in the mark between 4 and 8. żIs that the right pressure?
The temperature gauge is usually in the position you see in the picture. Occasionally it goes between N and H, but only for short periods of time. My car was recently checked in depth by a Classic Jaguar expert mecanic. He cleaned the radiator inside and out (not just a flush, but a professional cleaning to remove any sludge that might have been there), put a new thermostat, replaced all the original rubber hoses by new ones, checked electro fans and filled the circuit with a special kind of waterless coolant that is suposed to be the best of the best. I am positive that the coolant system is working perfectly, but I just want to re check with you all if the temperature reading is ok.
Thank you in advance for your help.
The only AJ16 I have are the X300, and they are the same set up.
That oil pressure is about the same, but that Temp is a tad high. Mine sits just short of the N, on the C side, and rarely gets into the N at all, even on 47C days.
The new stat may be a higher temp than needed for your market.
I used a 82C Dayco (DT58A) brand stat. The OE stat is 89C.
Get shot of the waterless coolant, say I. It will make the engine run hotter than with water as, something they do not tell you, 100% glycol - which is what waterless coolant is - transfers heat considerably less efficiently than water, (or 40% concentration of antifreeze - 40% glycol).
But first:
Was your mechanical fan clutch renewed?
Is you auxiliary fan working correctly?
Get shot of the waterless coolant, say I. It will make the engine run hotter than with water as, something they do not tell you, 100% glycol - which is what waterless coolant is - transfers heat considerably less efficiently than water, (or 40% concentration of antifreeze - 40% glycol).
But first:
Was your mechanical fan clutch renewed?
Is you auxiliary fan working correctly?
AGREED.
I missed that bit, good pick up Greg. It was the best of the best here a while back, hard to find now I am told, but I have never looked for it.
Good quality coolant with Demin water, engine will love it, and you.
Waterless and coolant shouldnt be used in the same paragraph. Im no expert, that is just my walk by theory.
I have a few walk by theorys and they usually have to do with people I have worked with and are usually proved right eventually.
ie, I walk by and shake my head at what they are doing.(or the way they are doing it)
Are you sure your car has the 'comfort' gauges? I recall, perhaps incorrectly, that Jaguar went to made the change circa mid-1994. I'm only on my first cuppa coffee, though, so I can't be held liable for anything I say
I agree that the temp reading is a tad high, as Grant said, especially if that reading is under mild ambient conditions. If you want to get down to a more comfortable reading (I suspect most of us would) I agree with the suggestions given.
Where did the needle sit before the cooling system work?
Under what conditions does it go higher? If this is somewhat random it might suggest and air pocket in the system
My experience with AJ16 temp readings is the same as Grant's. I had a '95 XJR for years with the comfort gauges. The temp was always just just a needle's width shy of touching the "N". On one very hot day I decided to check the actual temp reading with my scan tool. The needle hit its just-shy-of-the-N reading at 174şF and remained there until (at least) 205şF. The coolant temp never got higher that day so I couldn't tell how high it would have to be before the needle moved.
Thank you all for your helpful responses
The coolant that my mechanic has put in the car is Evans. I have read that, as some of you have pointed, such coolant is less efficient than water in conducting heat, but it has many other advantages.
By mechanical fan clutch I guess that you mean the viscous fan. It was checked and it seems to work properly. When it comes to the auxiliary fan, I specially insisted in it being checked because summers in Catalunya can get very hot, and traffic jams in August are common. The mechanic saw that the sensor of that auxiliary fan was not working properly and put a new one. Now it works as it should or so I think because at low speeds or even bumper to bumper traffic, the temperature goes slightly lower than at highway speed. I think that such detail proves that there is something in the radiator that increases air flow when required.
My XJS was manufactured in 1995, so I am pretty sure that it has "old school" gauges because none of them points exactly at the middle. Water boils at 100 degrees centigrade and most engines work at 90 degrees, so if the gauge showed the real temperature the needle should be very close to the red zone all the time. My mechanic knows of my almost obsession for keeping a cooling system always in perfect order and he knows XJS's like the back of his hand (he himself owned a V12 for more than 15 years), so I am sure that he has done a good job. But several oppinions are better than just one, and more when they come from actual owners. That is why I wanted to know yours.
80% water / rest glycol and water wetter. My Jag mechanic suggested this as he used to race v12's and its so much better. Just enough ingredients to prevent rust and lube the system. Your in Spain? You'll need it thats a hot climate.
Your AJ16 will run on pure glycol without any hassle. Running V12 on it = pure suicide as glycol runs hotter. Waterless coolant was designed for diesel engines to run them hotter due to emissions. It won't cause a pitting to cylinder sleeves (exposed in new engines). Best waterless coolants are having 70% heat capacity of the water. Regular falls into 50%. It has no benefit for old schood petrol motor. Unless you're topping your coolant up with tap water or you've picked wrong coolant type (phosphates and silicates). If in emergency, you will top up waterless with a drop of water - your engine will be exposed to corrosion. Now think how your mechanic got rid of all the water from your system? (just ask him). Also - mechanics are buying barrels - not bottles. Waterless coolant will absorb the moisture from the air if the barrel is unsealed - same as the brake liquid (how old is the barrel of your mechanic?)The best of the best is ELC type. Big players are using it for heavy machinery where fault/downtime equals heavy money. Sorry to dissappoint you.
best of the best is ELC type. Big players are using it for heavy machinery where fault/downtime equals heavy money. Sorry to dissappoint you.
Yes, any semi-truck dealership will have it for cheaper than your local parts store usually and it'll be the 900,000km (lifetime) variant that meets Caterpiller specs for heavy on/off highway use.
Once again, I thank you for all your help.
Temperatures now in Barcelona are getting above 30 degrees celsius. Yesterday I was going uphill in a local road full of curves so I had to demand the engine more than usual and the temp gauge reached a level that I was not comfortable seeing. I know that this waterless coolant boils only at extreme temperatures that can only be reached if driving in Hell, but I think I will ask my mechanic to substitute it by a normal coolant, which is what this engine was designed for when created. As with all my other cars, I will use the highest possible quality coolant and replace it regularly because we all know that even the best coolant does not keep its properties forever. I have a very relaxed driving style that will never force the engine, but I prefer a regular coolant that dissipates the heat more effectively than waterless one.
When it comes to the oil pressure reading, I have seen that around six is perfectly normal so I do not have to worry about that.
Very sensible. Use max 30% antifreeze, (remember 100% water is best for heat transfer, you will not need more than 30% antifreeze) plus two bottles of water wetter, all will be well. The engine will have to be flushed very thoroughly indeed. https://www.tec-racing.fr/red-line-w...-4_30-568.html
06-21-2020 | 04:24 AM
Right gauge reading
