Quick questions about repairs + replacing some parts

[burnsy150]

1. Not getting too good economy and i've replaced or serviced all the usual suspects besides the coolant temp sensor.

Was going to replace it but it had me thinking, my thermo fan comes on when it's about 3/4 on the gauge in which that would mean the ecu is getting the right coolant temp as the thermos coming on at 3/4 when its on the gauge as there are two different senders which would mean this confirms they are both in working order? but please correct me if i'm wrong, so should i bother changing it?

2. My auto box a fairly noticeable change between up/downshift on 2nd-3rd, more of a noticeable big thump than a clunk although it fair more noticeable on upshift but gets worse as the car gets hotter, just wondering if it could be an internal or external problem such as mounts or uni's but it only happens on 2nd-3rd so i'm not too sure, any thoughts? cars only done 130xxx fluid seems fine but is due for a service in about 5000

3. My mechanic put 15w/40 in my car but does seem to have developed a little more engine noise, i was thinking of trying 20w/50 mobil one synthetic maybe or no? would mind a reccomendation from personal experience..

4. Finally one of my idlers pulleys is worn (rhs to waterpump) ill replace it myself, just wondering how tight it should be when i put the new one back one?

thankyou all sorry for all these questions just thought i'd put them all out at once instead of starting many threads

[hako]

1....Pretty sure your assumptions are correct. What do you call "bad economy" I get 8-9 L/100Ks highway and 12-14 L/100Ks around town.
2....With only 130K the uni's/mounts should be OK unless car is driven hard. Sounds more like the auto needs a service and/or replacement as they generally give trouble around 150K although some get 400K.
3....20W50 is the factory recommended oil - a lot of mechanics use 15W40 as it suits most newer cars but is a bit thin for the V6 which is really a 70's design.
4....beware of the LH thread on the tensioner pulley if you decide to replace all. Not sure of the tensions but take care if the bolt goes into alloy.
Good Luck.

[vsiicalais]

hey mate, the trans may just need a service, mine was slipping and clunking a fair bit, took it in for a service and all was good, mine has done over 550,000km on the original trans no rebuilds, each time it either clunks or slips it goes in for a service. always comes back like new. only costs me $185- each time

[burnsy150]

bad economy would be less than 300km per tank around city, yeah hopefully it may just need a trans service, gee 550 on originals and still going strong!