Advice Please To Improve My Cars Engine

[chris5346]

hi,

I recently purchased a diahatsu excel 1993 with 160,000 km.

i'm happy with the car except for occasionally the oil warning light comes on at low revs :

the car basically ticks over at 1000rpm - if i have the aircon running the tickover revs drop to approx. 700 rpm.

if the engine's cold - the oil warning lamp may come on if the aircon is on also at tick over.

if the engine's hot (over half way to three quarters on the temp. meter) the oil warning light comes on at say 1100 - 1200 rpm.

so at junctions or sat in traffic especially when it's hot with the aircon running i'm finding myself having to press the gas pedal to make the oil lamp go out.

i read somewhere that putting a thicker engine oil may help with oil pressure ? would thicker oil make the car engine heat up quicket though ? or run hotter ?

i have found some 20W50 in tesco lotus - it's a cheap price - would that be ok to use ?

i have also seen some engine oil addatives which reduce friction and wear etc - would it be an idea to treat with that also ?

i don't know what oil is being used at the moment.

any advice welcome thank you.

[transam]

20/50 might fix the prob, if engine is worn then that is the only way to go. Do you notice any engine knock or rumble ?

[chris5346]

no i don't think so.

but i will check again,

how about those addatives i'm a bit worried they will loosen the engine and maybe make the engine more free ? reducing the oil pressure even more ?

is there anything i can do to make the engine run cooler ? maybe keep the fan running all time etc ?

or maybe using a coolent in the water system instead of plain water ?

it's not a major problem at the moment because here in chiang mai it's cold outside and i can choose when i use it.

if the oil light comes on sat at traffic for say 5 mins is there a chance something bad could happen ? does it help if i keep the revs up and switching off aircon etc ?

many thanks,

chris

[funcat]

no i don't think so.

but i will check again,

how about those addatives i'm a bit worried they will loosen the engine and maybe make the engine more free ? reducing the oil pressure even more ?

is there anything i can do to make the engine run cooler ? maybe keep the fan running all time etc ?

or maybe using a coolent in the water system instead of plain water ?

it's not a major problem at the moment because here in chiang mai it's cold outside and i can choose when i use it.

if the oil light comes on sat at traffic for say 5 mins is there a chance something bad could happen ? does it help if i keep the revs up and switching off aircon etc ?

many thanks,

chris

...how long do you think you can keep it up running like this...look for a mechanic..

[chris5346]

apparently the light has been coming on for the past 9 months or so.

it has also done many trips to mai sai in that time,

a couple of weeks ago i took it through some mountain roads from mai rim to hang dong it took a couple of hours up some steep hills and engine was fine.

i'm due to take it to udon thani next month so i'm thinking of doing the oil change before that.

it's just about the addatives will they help or make things worse.

i'm hoping that maybe in the last service they used a thin oil.

i don't rely on the car it's just a luxury item, i don't like driving in chiang mai much.

[kartman]

There were 40 replys in the last thread you started about this i expect it will be the same advice this time .

[thaicbr]

do an oil and FILTER change.. maybe the oil filter has never been changed. A heavier oil will not hurt (just on the colder days up there warm the engine for a minute or so before moving)

I had a Thai friend who had a car for 4 years and 56,000km and NEVER HAD IT SERVICED in that time. when finally she started having starting problems her neighbour checked it over and the oil was sludge and the battery was knackered. Her excuse the garage never told her to service it.

[chris5346]

it had a new oil filter last service , i'm hoping that they used thin oil last time and that's contributing to the problem,

a japanese guy has owned it for the past 5 years and has looked after it well, servicing and repairing faults with exception of this oil lamp.

the 20W50 oil i have found only costs 250 baht ! will the quality be ok ? or should i find some better stuff ?

i'm thinking that if i use the lubricating addative that reduces friction that may make the oil flow too well and actually reduce the oil pressure in the system ?

i guess the first thing to try is just the thicker oil then maybe addatives if no improvement .

[murray122]

the 20W50 oil i have found only costs 250 baht !.

You get what you pay for.

Also, wouldn't recommend using plain water in your cooling system. Coolant raises the boiling temperature, plus acts a lubricant and inhibits corrosion.

[WarpSpeed]

There were 40 replys in the last thread you started about this i expect it will be the same advice this time .

Was thinking this sounded of deja vu...

Edited January 25, 2012 by WarpSpeed

[Crossy]

Definitely deja-vu, last thread was before he bought it (it was a Hyundai then).

Whatever, do you want to fix it or mask it?

Putting thicker oil or one of the oil additives (would be STP or Wynns in the UK) will get the oil pressure up but to fix it permanently you likely need to get new big end and main bearing shells and a new oil pump. Your local car-chap should be able to do the job for a pretty nominal fee.

Be aware that if you continue to run it with low oil pressure eventually the damage will go beyond anything that can be fixed with shells at which point a new or re-ground crank will be required.

IMHO you should have it properly sorted now.

[transam]

Think it possible that the sender unit could be miss reading stuff, l say that cos it's been doing it for a long time with no bearing damage. At idle you only need a few psi to float the bearings. The light might be flashing but you have 10 or 15 psi.

On the engine in my avatar pic l had the same problem, 25 psi at idle when hot but 100 psi at near 7K , the fix, bought an adjustable sender unit. , OK for over 20 years.

[chris5346]

yes sorry it's the same car and thread,

before i bought the car i thought the problem was due to the oil pump turning slower at tick over (700rpm) when the aircon pump was running because that's the only time the light came on but since i've been driving it around i have noticed it comes on even with the aircon off and when the engines at its hottest the light comes on at 1200rmp,

so it looks like the problem is a bit more serious that i first thought.

i will try a thicker oil and put some coolant in the water as suggested thank you.

the previous owner told me he asked people about this problem and i think they flogged him off saying it was due to vibrations?

i asked if had taken it to main dealer and he said no.

i was trying to find out what oil was used in the last service and how many kilometers had he done since the light has been coming on but with communication problems i couldn't find out any info. from him.

he did say that the oil filter was changed last time.

i'll change the oil and see what happens,

i'm still unsure about this cheap oil at 200 baht and putting a 1000 baht addative to it seems backward to me ?

thanks for you help,

chris

[mogandave]

Adding “coolant” will make it run hotter, not cooler. If it’s getting hot, you need to flush the system several times, refill it and see if it still gets hot. If it’s still getting hot, you have a problem in the cooling system. That said, you should be running coolant, or at the very least a good anti-rust & water-pump lubricant. If money is real tight, a pint of water soluble cutting oil works great.

When you are uncertain about a car’s maintenance, a good first step is to change the oil and filter and use either a flushing oil, or a flushing additive and drive it at speed for about 10-20 minutes and them change the oil and filter again.

Given the climate in Thailand, I would run good quality, straight grade (30W or 40W) oil without any additives. Oil is about the worst place to be trying to cut-corners.

A decent shop should be able to hook up a mechanical oil pressure gage and determine if you just have a sensor problem or a pressure problem.

[transam]

Even if the thing is running hot the oil pump still does it's thing to provide ''pressure'', which controls the sender unit. Quick info for you is to change the sender unit. If the light still comes on then you have bearing damage/wear. Means a crank grind and new shells. No way out l am afraid. BUT, if the engine is surviving then l would forget it.

[Hssl]

take it to B quik, get them service the bloody thing and stop guessing!

[transam]

take it to B quik, get them service the bloody thing and stop guessing!

Unfortunately a service proves nothing. A motor guy who knows his stuff will point to a possible problem. THEN, a strip down will reveal all.

[chris5346]

the cars not running hot , it's goes upto about one third on the temp gauge after 10 mins driving and mostly stays around half way.

if sat in traffic etc or a hot day here the temp. goes upto two thirds on the temp gauge and i presume the fan cuts in ?

i don't know i haven't had the car long.

if i do short journeys or on open road the temp gauge stays low and no signs of any problem with oil lamp also.

i was reading some of the addative bottles today, some contain ptfe and they are synthetic based ? can i add them to normal oil ?

some say they reduce engine temp and wear etc so maybe an idea to try one ?

or is it going to be a case of i add the engine treatment and i notice/see no difference ?

i have also been looking at 50W oils and there's many here designed for pick ups and diesels etc. i did manage to find one small can of havoline 20W50 in big C which looks the best so far if i can find a large bottle.

thanks for the tips.

[transam]

the cars not running hot , it's goes upto about one third on the temp gauge after 10 mins driving and mostly stays around half way.

if sat in traffic etc or a hot day here the temp. goes upto two thirds on the temp gauge and i presume the fan cuts in ?

i don't know i haven't had the car long.

if i do short journeys or on open road the temp gauge stays low and no signs of any problem with oil lamp also.

i was reading some of the addative bottles today, some contain ptfe and they are synthetic based ? can i add them to normal oil ?

some say they reduce engine temp and wear etc so maybe an idea to try one ?

or is it going to be a case of i add the engine treatment and i notice/see no difference ?

i have also been looking at 50W oils and there's many here designed for pick ups and diesels etc. i did manage to find one small can of havoline 20W50 in big C which looks the best so far if i can find a large bottle.

thanks for the tips.

Forget additives.

You can buy 5 ltr 20/50 near anywhere but please read my posts.