Thomas Varghese

Absolutely correct. There must be a reason from Nissan engineers why they don't fill up the reservoir. This can only be answered by them. We are novices and learning from experimenting.

Thank you @Gaurav. Enjoyed your technical views on the fan clutch. I have 1 doubt if you may please clarify. The fan was not making the roar in OEM silicone fluid level and was keeping the engine cool on tarmac. As per mechanics explained by you and various other forums the reservoir should be full. It was not the case with 2 fan clutches we experimented with. Both are relatively new. When we topped up the reservoir with additional fluid the temperature dropped. The fan roars when we accelerate and the sound wanes away soon after. If by theory the fan clutch only operates at constant speed then why does it roar when topped up? The roar is caused by increase in air suction which is the result of increased speed of the fan clutch. If not it should roar everytime the fan clutch engages.

Ohh I forgot to mention. The 1st tester of this technique was @Shaaz Sha. We discussed this problem of over heating and the probable solution of filling up with silicone fluid was suggested by our regular mechanic in Ajman. @Shaaz Sha promptly tested it day before yesterday and found his engine temperature maintained at manageable levels and promptly reported to me. I did the same yesterday and found it worked for me too. Everything is good except for the fan rrrrooooaaaaaarrrr when you accelerate. @Shaaz Sha also complained about the roar but its still ok if we can offroad with AC blasted on without overheating issues. I fixed additional fans for solving overheating issue as it seems these fans are bought by everybody and installed. The fans are sold like hot cakes from the shops as outside temp rises. As you correctly said these fans block air flow and it actually only helped when the car was in idle by aiding the AC to cool whereas the AC was cut off during this idling time. If you run these fans during running time it tends to increase the temp guage and I suspect these fans disrupt the air flow to the main radiator fan. By the way @Shaaz Sha's fan clutch also took 2 tubes of silicone fluid to become full. Its also a relatively new fan clutch. I suspect the manufacturer doesn't fill up the reservoir completely for some reason known to them.

I replaced the fan clutch with a new one just 2 weeks ago. The thermostat valve was eliminated at the same time and coolant is now free flowing into the engine. When I removed the fan clutch to refill the silicone oil the reservoir took in additional 2 tubes of 18ml to become full. As its a new fan clutch and after thorough inspection no leak was found. My older fan which was replaced 1 year ago was found with a leak and that is why new fan clutch was bought.

Take good care of your car and it will run for ever

Its simple @Chaitanya D. Remove the fan clutch from the engine. Separate the fan clutch and the fan. The fan clutch is made of 2 circular parts secured with 4 or 5 screws. Unscrew them and tap on them to separate it. Before you do this make sure you mark the 2 pieces so that when you assemble them together the grooves inside align. There is a small wedge inside a groove in one of the circular ring and make sure you don't lose it when splitting them. Pour the silicone oil purchased previously from the AC spare part shop and reassemble making sure the outer O ring is perfectly placed and not pinched. Re fix the fan to the clutch and reinstall this assembly to the engine. The silicone oil is made by Toyota for LC and is 18ml in a tube. Grade you get here is 10001 cts which costs 20 AED. It would have been better if you get the lighter 7000 CTS grade but is not available anywhere. The principle behind this is the viscous fan clutch is actually a torque convertor you find inside your ATS gear box. There is a bi metallic strip which controls the opening and closing of the valve which holds the viscous fluid inside a reservoir. The valve opens when the bimetallic strip reaches the pre set temperature and releases the fluid into the grooves of the fan which then locks up both parts as a clutch. The fan then starts to rotate. Unfortunately the cars manufactured in America is calibrated to engage the clutch at a higher temperature to reach the optimal operating temperature of the engine faster as they have cold climate. So the fan doesn't engage for sometime as cold air is anyways flowing over the radiator. The scenario in middle east is different and its very hot climate. Its more aggravated when we take our cars to the desert. We cannot calibrate the bi metallic strip. Its pre set. The only thing we can do is increase the volume of the oil inside the clutch so that the grooves get filled up faster and lock up the fan. After this mod I think I put one tube more as the fan engages much early. Should have tried with 1 tube and then increased gradually if not satisfactory after a drive. I am not very unhappy too as my car cools even when idling as the fan gets engaged fast but the fan roar is something you have to live with when it engages. The increase of the fluid makes the fan's ratio to the pully also more and it runs faster. As I understand the max rotation of the fan with a fan clutch is not equal to the rotation of the water pump and probably fixed at 70 to 80%. In this scenario it almost reaches to 90% of the water pump's rotation. I suppose this is what makes the fan to roar. Its not always but you notice it while idling and accelerating. I have a good audio system and it doesn't bother me much. All this info I got from X forums prevalent in Australia as they have similar issues of overheating as theirs is a hot climate in the desert similar to Middle East.

Dear All, From the start of the summer season I have experienced engine over heating issues in my X. I have experimented various ways to over come the same and spend lot of time and money to solve it. For the beginning I flushed the cooling system and cleaned it. No use. I changed all the pipes, coolant. Didn't help. Changed the radiator and the fan clutch. Result was same. Fixed additional electric fans, the over heating issue remained. I was at my wits end and had almost decided to pull out from offroading altogether during summer. It was going to be a tough decision as I don't want my car to suffer at my off roading. Whatever time I do off roading whether its early morning or afternoon or night some sort of overheating issue remained. Did more and more research on various X forums and found out there is a solution which has been overlooked by so many mechanics. The fan clutch supplied by Nissan or for that matter any other manufacturer can cater only for general use and if manufactured in America it is calibrated keeping the colder climate into consideration. It cannot be used in hot demanding conditions as it comes in stock condition or for vehicles which tow heavy loads or for offroading. The additional electric fan which I fixed in front of my radiator was actually aggravating the cooling as it disrupts the air flow when the main fan is running. That additional fan only aids cooling when the vehicle is at a stationary position when the main radiator fan slows down or stops. 400 AED and time spend sourcing the fan and fixing it went in waste. 1 day I forgot to switch off that fan and was stranded as it drained my new battery. The overheating even took a toll on me as the ECM cuts off the AC when the engine gets overheated and imagine running in the desert now without an AC. I was feeling exhausted and delirious. EUREKA. I found out that the stock fan clutch can be enhanced by adding little more silicone fluid inside the reservoir. I decided to give it one last try or give up summer offroading altogether. Bought 2 tubes of Toyota LC fan clutch silicone oil rated at 10001 CTS and opened the fan clutch and poured into it. Each tube is 18ml and costs 20 AED in a local AC spare parts store. The car runs 10 degree cooler and takes little more time to reach operating temperature but the guage needle is only half way through from C to the 2nd level whereas it was over the 2nd bar when running on tarmac till now. Wow. Now my AC runs cooler than before, cools at even idling but there is a sound of the fan running even at idling speed. I don't care as I have a good audio system installed. The fan is tighter than before when the engine is stopped and engages much faster so that engine starts to cool early. I believe as the fan engages much earlier it engages the water pump which in turn circulates the coolant even more efficiently. Maybe I could do with just 1 tube of silicone oil instead of 2 to eliminate the fan engaging sound. Another thing I noticed is that the engine oil pressure guage runs more higher than it was previous. I suppose this has enhanced the oil circulation inside. No idea what is the connection between fan clutch and engine oil circulation.

I have 1 spare which @Hisham Masaad has given. I can give you.

Thank you @Ale Vallecchi and the co drivers who participated in this drive. The convoy was moving as a well oiled machine and as far as i could see the distance between the cars remained the same come whatever maybe the terrain and was driving and driving. Even though @Ale Vallecchi promised only half an hour drive the convoy kept moving and moving in total radio silence for about one and a half hour. Incredible drive.

wish to join but my 2nd vaccination is on 17th. no idea how my body will react to it.

well said @Rizwan Waheed. Its really commendable that you reached IM level with a 3.0 Ltr Pajero. That shows your skill. Keep going buddy.

Congrats @Russ. Push the raptor to IM level

@Ale Vallecchi I have added myself to the drive. Thanks for reposting.

@Shaaz Sha has bought a new 4 cylinder compressor which can inflate all 4 tires under a minute or two. It has double outlets for inflating and its sort of semi automatic. I don't know the brand name but as per @Frederic it has some great reviews in the internet. Cost is around 600 AED.

Thank you @Chaitanya D for the appreciation. The fact is I didn't like the night pictures as my lenses were dirty and it shows in the final rendering. The dust on the lenses won't show in day time pictures but yes it appears in the night pictures as it scatters the light coming from the powerful headlights like an unruly prism. Unfortunately when I decided to carry my camera I knew the lenses were dirty and it might show but it was too late to sit and clean them as I would have missed the drive then. The night time pictures with a DSLR is not as smooth as a point and shoot camera or a smartphone as too much attention has to be given to the settings to properly capture the scene. Its a time consuming process and you cannot do it in a hurry. 1st of all its impossible to take pictures at night handheld with a DSLR as any shutter speed less than the camera lens focal length is going to result in camera shake. TRIPOD is a must. I had to use the tripod as shutter speeds were more than 3 seconds instead of the usual 1/50 or 1/100 or 1/250 and faster speeds depending on light condition during daytime. Night time photography is more creative than daytime as you can produce streaks of light emanating from the car headlights or tail lights which when properly processed gives a stunning look. You cannot do all this in the middle of a drive. We have to dedicate a drive completely to capture night time driving pictures with a DSLR. The results will be stunning though. The focus of that drive should be only photography and not drive challenges. Hopefully you will organize a drive soon focused on night time desert driving pictures. I would love to take a motion blur picture of the cars during twilight hours if possible as I don't have an ND filter to stop down the shutter speed to less than 1/30 sec during daytime so that the motion blur is captured. It gives a sense of motion and emphasizes on the motion of the car instead of just still photographs of car I take now.

Great drive @Kailas. Hope I did ok as a 2nd lead. Still figuring out how to follow a Wrangler in a Xterra. Wranglers have a very good linear torque and can power up from anywhere whereas Xterra driver has to keep the momentum going when climbing or else get crested or have a refusal. The balance is very critical and very difficult when following a Wrangler. Sorry to have come close to you during climbs by not giving you enough time to warn me but I think I could wriggle out of the situations except for once when I got bridged when coming down. Thanks for pulling me out. Xterra simply cannot power up like a wrangler after losing momentum on a climb and I couldn't break the momentum so had to keep going up & up when following @Kailas and sometimes had to come close. Overall the convoy was good at negotiating the challenges without much stucks or refusals which made me experienced drivers reflect back on our newbie, fewbie days and feel ashamed about those times. The new fewbies did amazingly well for the difficult terrain. Thanks @Rob H for a great center forward and what should I comment about our most experienced sweep @Chaitanya D. Every time @Chaitanya D has new things to teach me. With @Chaitanya D learning never stops. Looking forward for more drives with all of you in the future.