Ask Xulfiqar - An Automotive Encyclopedia

[k180233]

Did this on Saturday. Though the valve looked pretty free moving/not stuck, but still I got it cleaned and lubricated, connected it again, re-calibrated the base idle again and the issue persists i.e. either it can compensate for load of transmission or AC compressor, when both are engaged the RPM falls. And after driving for a while/bringing to operating temperature, with AC + transmission it idles 550-600 RPM, insanely rough.

Anyways, I set the base idle at 900ish so at load it idles at somewhere 700ish, it ran fine for a day or two, but at a cost i.e. when starting overnight cold it's now doing that idle surge between 1300-1700 when there is no load.

Btw, mechanic also tried to calibrate with that spring like thing at the back of the IACV, but it just doesn't take both transmission and AC load.

What should I do? Decrease the base idle and let it run rough at 650ish or what?

[k180233]

Btw a bit off topic, I have also noticed some blow-by through oil cap at idle. But it disappears on a bit higher RPMs (2000ish), have also noticed manifold going bit oily too.

My mechanic thinks that's the issue why "gaari ideal p load ni le rahi, engine weak hogaya hai". Doesn't make sense though as compression test done by himself had 160-170psi throughout. And neither there is oil reduction or any exhaust smoke.

I am suspecting something wrong with PCV system behind this blow-by. What's the sure way to diagnose that? Whether it's the PCV or something within the engine itself?

Thanks.

[sleeper]

Salam @Xulfiqar Bhai,

As the winters have arrived in Toronto, i got delayed\lazy in getting my 06 Matrix undercoated earlier.. but will go this weekend.

I wanted to ask, should we wash the car before undercoating? Car is pretty dirty from few previous rains and not cleaned in 3months

Then after undercoating is done, how often should i wash the car to get rid of any salt deposits?

Also if just normal washing it monthly, does it affect the fluid film undercoating in anyway?

[muhammadharisakram6]

does warrenty void on using after market tires, general tycon was installed and due to wear and tear i changed to dunlop eco on picanto?

[dayrider]

Nope, if its the same size, warranty doesn't void

[ahmedfawwaz250]

@Xulfiqar what's the difference between Dexcool and Caltex coolant?

[imran2155]

Aoa,

Corolla Grrande 2018
Currently at 110k kms
Mileage city is between 11 and 12
Mileage highway at 110 speed is between 14 and 15km/l

Car has no issues except that now the engine sound is more noticable when accelerating. I checked on Quora and some people say change oil grade to a thicker oil after 100k kms. But other folks say 100k is nothing for these engines and oil grade should not be changed from what the company recommends.

Can you please help with this. I've been using Toyota recommend 5w30 since day 1.

Thanks in advance

[kameetaha]

Check belt accessorise like tensioner, bearings and alternator. And yes oil grade should not be changed from what the company recommends.

[Xulfiqar]

Its the same OAT type coolant without the orange dye which would make it dexcool.

[Xulfiqar]

There is never a milestone in any car engine life that makes it qualified for heavier engine oil.

Use what the manufacturer tells you to, for abnormal noise, have mechanic find it out, maybe your engine mountings (foundations) have settled or have external noise.

[ahmedfawwaz250]

I thought there were some difference in their formulation.

[Xulfiqar]

Havoline/chevron/caltex developed dexcool with GM

Almost All universal coolants are dexcool without the proprietary dye formula.

I recall the old bottles of caltex sold in pk literally said dexcool approved on the back of the container, it was the original GM specification number.

If you are filling it fresh in your car, completely degrease and derust the system then fill it up, make sure no leaks exist and its good for the next 100,000 kms at least.

[ahmedfawwaz250]

I want to switch from Toyota Pink to caltex, but i have heard that it creates jelly because of the phosphate deposits inside the system, there is no rust so i dont have to use citric acid,
How can i degrease it ? Do i even need it?

[Xulfiqar]

You can fully drain and then flush the system with distilled water to get everything out if there is no rust or oil residue.

[ahmedfawwaz250]

Thanks alot sir

[Xulfiqar]

Do you know how to fully drain your system? And how to positively flush it out?

[ahmedfawwaz250]

I first drain the coolant from the radiator, then i remove the heater pipe , connect a garden hose in the radiator, and start the car for few minutes,
I dont know if this the correct way to do it, but it is just easier and faster way for me , and it also cleans out everything.

I am just too lazy to remove the thermostat and blow out the remaining water in the system, that why i am opting for a concentrate rather than 50/50 ,

[Xulfiqar]

I would suggest to not the job, running the engine with a garden hose connected is a sure way to damage something like a headgasket.

Does your engine thermostat regulate cold water inlet or hot water outlet?

[ahmedfawwaz250]

How does this damage the headgasket?

Its cultus efi, i disconnect the heater pipe which is behind the thermostat, then i reconnect it and remove the other heater pipe which is connected to the metal pipe ( connected with metal pipe). Then i clean the upper radiator hose pipe as this process doesn't clean it.

[Xulfiqar]

You are shocking the system with a massive temperature difference with cold running water and a firing hot cylinder head. It can warp it and cause the sealing surface to shift causing a leak.

In workshop when we have to do a hot flush clean (greasy gum type residue in diesel engines) we use a a hot water line from a geyser.

For all other flushes like acid or gentle soaping etc, the flushing is done cold on cold / cool engine with tap water at normal temperature level of 22C. Final rinsing it done with distilled water with a pump or a bucket with a pipe connection or a simple funnel with a hose - but making sure that it can remove everything out.