Hi sifus, my Mvyi is 9 years old and 140k km mileage already. Regularly sent to Perodua Service Centre for servicing.

I recently found out that radiator reservoir tank dropping rapidly. About 10days, then I need to refill again. No sign of overheating. I was quote by Perodua Service Centre to replace the whole system water pump(RM420), radiator assy(RM285), Labour(RM150) and others+GST (RM80).

Googled and find so many different causes and solutions. I checked no sign of leakage coloured spot from radiator coolant.

I would like to know
1. Does Perodua Service Centre provide troubleshooting radiator and replace the spoilt part? or I should sent to other workshop for radiator servicing but since im used to service at Perodua no idea which shop to go.
2. Just ignore and constantly refill the water into reservoir tank?

Wanted to seek advice because huge blow to fork out RM1k. Hope to get some advice before proceed.

dont ask produa ...la bro...go to the radiator specialist.. cheaper...lagi

I see. Sorry noob here did not know there is such a shop radiator specialist shop. I am used to service at Perodua no idea which shop to go. I can just go any radiator specialist shop? any recommendation at kluang, skudai or johor bahru area?

I am not familiar with the myvi, but go take to a shop and do a pressure test. They will pressure the cooling system to 1.5 bar and see if there are any leaks.

Many leaks happen only when the car gets up to running temperature and under pressure.

If there are no leaks, you can start by changing the cheapest item, the radiator cap which would would be a few ringgit. A 9 year old car would probably have hardened hoses, and if you have not changed them, perhaps it is time you do so. A set of hoses shouldn't cost more than 100 for a set. Once you take off the hoses, you may see if the steel hose necks are not corroded...replace the neck if corroded, or in some instances if salvagable, a mechanic can slap on more RTV silicone to seal it better.


but having to refill water every ten days sounds very serious to me. The leaks should be quite easily spotted.

Water pump leaking would be rare, given if you had only run 140k, but not an impossibility. You can only spot any leaks from the water pump after you remove the accessorize drives and the timing cover.

Regardless, a normal outside mechanic would probably be better experienced to catch these sort of leaks since they would be more experienced dealing with older cars than the ones at the dealer.

Get it properly diagnosed before replacing anything.

Thanks a lot jaycee1 for your great advice. You put it into step by step manner easier for car illiterate guy like me easier to understand.

I feel enlightened and totally agree you. Haha.. I will follow your advice by changing the cheapest item first. I will start with the radiator cap and radiator hoses. Even my window strip rubbers are hardened and ripped apart so I believe changing rubber hoses is a must.

The other parts like steel hose neck, water pump, etc I will let the mechanic to decide needed to be replaced or not. I have been trying to look for the leak coloured spot for a month. Check everyday, but could not find any. Might be the water pump. I think I have to drive around town area to search for suitable shop.

Go to any outside workshop locally to establish whether radiator cap is faulty or water pump leaking ........ provided you found honest and trustworthy ones.
Forget about your Perodua SC! I consider their suggestion as being not honest and competent.

This post has been edited by zeng: Jun 7 2017, 08:13 PM

So far, how much water have you topped up? You may want to check your engine oil for water contamination. Can use the dipstick and engine oil filler cover to check for sludge or milky stuff. The missing coolant could be leaking into your engine.

Start your car with aircon switched off and let it warm up. Open bonnet and observe for any water dripping.

May I also suggest changing the radiator cap first, before touching the radiator hoses? Meanwhile, do check the engine oil appearance regularly.

I tried to check on the radiator cap rubber this evening, seems like still in good condition. I never know theres rubber layer at radiator cap until today. Maybe need professional mechanic to double check on it.

haha. From my experience, Perodua SC that I visit seems not bad that why I sent there with peace of mind. But still for this problem I will look for other repair shop.

About 10-15 days, I have to top up full radiator reservoir tank.

Thanks for your suggestion. Tomorrow will check whether water contamination occur or not. Its dark now. haha.

This evening I tried to check on the radiator cap rubber, seems like still in good condition. I also checked by starting engine and off aircon (learn from google) but could not find any water dripping except the air con. And from now on I will check engine oil regularly.


Thanks a lot sifus. I learned a lot today. Should have understand my myvi more.

You are losing water from water reservoir I guess that shows no or minimal pressure leak.

Since you can't find leak when the engine is running, try to look for leak on the second day before starting the car. Inspect every hose neck especially the bypass hose. The longer the car sit idle the better because you need the system stays as cold as it could.

I assume you did check the reservoir tank for leaks, right?

To be honest, I can only observe from top not dare to open up the things to check the bottom are even the reservoir. haha. I can only use eyes observation, top observation seems ok, might be leaking from neck or bottom area as suggested by jaycee1.

I see. Did not know if left idle can identify the leak easier. Thanks for the advice. Will check it in the morning before work.

I also did engine oil containmination checking, seems ok to me. Yesterday went around my area, spotted two potential service shops. The uncles seem reliable with many customers, will choose either one of it. Can only be sent for checkup next weekend, gotta need to use my myvi.

Well reason being to check at cold because a lot of time the coolant evaporate during hot due to very minimal leak. It is very unlikely to check for coolant stain because the coolant is already dilluted too much.

At cold the vacuum in the system will start filling up by withdrawing coolant from reservoir. It will then start to leak when the cooling system is filled.

Just sharing some tips.

My family's ol cars used to run on plain water (pipe water) without coolant, until 1 day one of the cars kept needing top ups like your scenario and could not find the cause even after replacing the cap (its usually the most common cause) and searching for leaks. I ended letting out some water in the radiator and poured in 2 bottles of cheaper (not the branded Toyota or Royal Purple) Nasa coolant just to 'dye' the water. Sure enough, a couple of days of driving around later, dried stains from the coolant at the radiator top cover showed the culprit.

This post has been edited by Deja Vu: Jun 9 2017, 08:34 AM

If this happened, it is very serious. Coolant leaking into engine crankcase, most likely a busted cylinder head gasket. Need to take apart the engine to clean out the sludge.

And one more thing, if you need water to top up your coolant, use only distill water (pure water, air suling, Spritzer selling them in 9 liter bottle). Normal tap water contain mineral that can cause scaling in the surface of metal (mineral stuck to the metal surface), reducing their effectiveness in heat transfer in long run.

This post has been edited by Kosumaledoko: Jun 9 2017, 10:03 AM

wow. thanks for the great info and knowledge.

i checked this morning and i realized there is one part seems like rusted and little water leak stain. (from my observation and opinion.

Your issue seems like similar to mine. Radiator upper tank may be the issue for me too.

Thanks a lot for your tips. lancer122 also having same issue radiator top cover.

Sorry maybe noob question. May I know the dried stains at radiator top cover, need to open up to check or can be observed from outside?

hopefully mine is not that problem. by my car illiterate guy observation, engine oil from stick seems ok.

have been using pipe water for few months. yep. a great guy also pmed and reminded me to use battery water, i assumed thats the air suling. thanks for the tips also. hope other guy reading this wont be doing the same mistake as mine.

You can view it without disassembling the radiator. The leaks that I've gotten so far are between the plastic top cover and the brass/aluminium/alloy radiator body where its clamped. Leaks here happen when the plastic edge disintegrate due to rapid temperature changes.

This is exactly a leaking point.
Clean it up, and it should help ....... and may possibly solve your problem.

That rust sign on the connector looks like a good indication of a leak. If that is really the cause of it, you might also want to consider checking/replacing the radiator hoses as the long returning hose on it looked bulged at the edge of the clamp.

This post has been edited by Deja Vu: Jun 9 2017, 12:37 PM

alright. will check on the radiator top cover too after work.

after a longer look at the hose, it is really bulging. i did not even notice it although i checked it so many times. thanks a lot for the great info. with just one picture, superb eyes and experience there.


great. hopefully it is the problem. will change the T and piping hose as well.

FYI, The smaller hose is a bypass hose. It allows water to flow through even thermostat is closed.

The 2 rubber hoses connected by the corroded pipe is upper hose. If the corroded pipe is slightly wet to touch in the morning before starting the car then it is leaking. Upper hose should cost about rm 20, bypass hose maybe cheaper. Very easy to DIY. Can use back the corroded pipe. Just need to sand it.