Ticking sound under the hood of Toyota Yaris Hybrid

[absolutebeginner]

Hello,

I just got alarmed by my neighbour that there was a strange ticking sound from under the hood of my two years old Toyota Yaris Hybrid. And there really was! So, there was a lightest drizzle outside but this sounded like a giant single raindrop was hitting the thin metal somewhere under the car (it went on and on even when the drizzle subsided, and rythm wise stayed the same when it started raining).

When we opened the hood, I noticed that the noise came from a left side but couldn't see where.

I also noticed that the rubber strip under the wipers is loose on the other (right) side so the paper sticker (with info from last oil change in the dealership) is completely drenched that it fell off.

My boyfriend thinks that there is a leak somewhere and that the water could seriously damage the engine, but if that is the case, why it happened on the lightest of rain and not when it poured cats and dogs in the last two years. I also checked the manual, but didn't find an answer.

Has anyone had a similar problem and what could it be?

Thanks in advance for any insight.

[FROSTYBALLS]

When was the 'ticking' sound occuring? Whilst the engine was running? After the engine was switched off?

[absolutebeginner]

Everything was off. The car was parked from the morning.

And when we closed the hood I started the engine normally, inside everything was quiet as usual (although, I didn't drive off)... except that sound which was heard only outside the car.

[GreenJuice]

Is it looking like you think this could be a dripping noise rather than a ticking?

Seems more likely to me, if everything in the car was off.

Logically, it must be coming from a higher level and falling to a lower level, so you should be looking for clues as to where the water source could be (from the light drizzle) and what kind of material would make that sound when tapped.

[FROSTYBALLS]

If you've been using the air con, which if combined with the heater makes for more efficient demisting, could it be excess moisture being expelled.

[absolutebeginner]

Yes, it was a dripping noise, but loud enough it actually sounded like there was a bomb ticking under the hood, which alarmed my neighbour.

We checked the engine area with a flashlight but couldn't see where the drops were falling (or from where), only that the noise came from within the left side. 

Anyway, I plan to check it again in the morning.

 

[absolutebeginner]

4 minutes ago, FROSTYBALLS said:

If you've been using the air con, which if combined with the heater makes for more efficient demisting, could it be excess moisture being expelled.

No, haven't used aircon or heater for some time.

[Sooty]

Could be simply that the components are cooling down?

Most metals will contract upon cooling and usually make a clicking noise.

[Konrad C]

On 1/12/2017 at 10:54 PM, absolutebeginner said:

No, haven't used aircon or heater for some time.

You should use the air-con to help demist the windscreen or at least for 10 minutes every few weeks, as lack of use will result in the seals shrinking. The gas will leak out and the system contaminated. Then when you want to use it in the summer - no air-con. My old Mk1 '98 Avensis had a working air-con when I sold it last year.It was re-gassed once every 5 years. My current car uses the air-con when demisting the windows. 

Ticking noise is contraction of various metal components during cool down, especially if two different metals are connected together. 

[kithmo]

34 minutes ago, Konrad C said:

You should use the air-con to help demist the windscreen or at least for 10 minutes every few weeks, as lack of use will result in the seals shrinking. The gas will leak out and the system contaminated. Then when you want to use it in the summer - no air-con. My old Mk1 '98 Avensis had a working air-con when I sold it last year.It was re-gassed once every 5 years. My current car uses the air-con when demisting the windows. 

Ticking noise is contraction of various metal components during cool down, especially if two different metals are connected together. 

unnecessary with the Prius, it has an electric AC system that is completely sealed so there are no external seals to dry out.

[FROSTYBALLS]

1 hour ago, kithmo said:

unnecessary with the Prius, it has an electric AC system that is completely sealed so there are no external seals to dry out.

The OP has a Yaris

[kithmo]

3 hours ago, FROSTYBALLS said:

The OP has a Yaris

Oops ! 

[johalareewi]

Same aircon system though. Electric powered by HV Battery.

[Devon Aygo]

On 15/01/2017 at 2:38 PM, kithmo said:

unnecessary with the Prius, it has an electric AC system that is completely sealed so there are no external seals to dry out.

Unfortunately not the case the car may have an electronic compressor but there is still gas and oil in the AC circuit and at least 6 joins in the engine bay all with rubber seals that need the oil circulating to ensure the seals do not dry out and contract this applies to all the Hybrid models

[kithmo]

By gas I assume you mean refrigerant and I can't see that any seals would dry out within weeks, it would take years, the average life of a rubber component is around 4 years IIRC. 

[FROSTYBALLS]

The OP's Yaris is a 2014 model - so now between 2 and 3 years old - and they said the air con and heater haven't been used 'for some time'.

[Devon Aygo]

13 minutes ago, kithmo said:

By gas I assume you mean refrigerant and I can't see that any seals would dry out within weeks, it would take years, the average life of a rubber component is around 4 years IIRC. 

I didn't mention any times scales I was merely correcting your statement about the systems being completely sealed as the Hybrid AC system is no different to any other automotive AC system in the respect of not using it will result in a loss of refrigerant over time. 

If the AC is used regularly the rubber seals can and will last well beyond the 4 years you mention, however bear in mind the seals on an automotive AC system are subject to significant variations in temperature, vibration etc which can result in accelerated gas loss all of this is mitigated if the AC is used regularly and seals kept lubricated. 

[johalareewi]

The AC in my gen3 prius was still going after 6.5 years (when I traded it in). No leaks, no regassing.

[kithmo]

14 hours ago, Devon Aygo said:

I didn't mention any times scales I was merely correcting your statement about the systems being completely sealed as the Hybrid AC system is no different to any other automotive AC system in the respect of not using it will result in a loss of refrigerant over time. 

If the AC is used regularly the rubber seals can and will last well beyond the 4 years you mention, however bear in mind the seals on an automotive AC system are subject to significant variations in temperature, vibration etc which can result in accelerated gas loss all of this is mitigated if the AC is used regularly and seals kept lubricated. 

The time scale I was referring to was the one mentioned by Konrad (the poster I was originally replying to) saying you have to run the A/C every few weeks to prevent seals drying out. As you probably know, the difference between the prius electric A/C and a conventional belt driven A/C is that the belt driven A/C has a shaft coming out of the compressor, connected to the A/C clutch. This is one of the most common seals that shrink due to the wear on it by a rotating shaft, this seal is the main one that needs lubricating and this seal does not exist in the sealed Prius A/C. 

[barrycoll]

On 12/01/2017 at 10:52 PM, absolutebeginner said:

Yes, it was a dripping noise, but loud enough it actually sounded like there was a bomb ticking under the hood, which alarmed my neighbour.

We checked the engine area with a flashlight but couldn't see where the drops were falling (or from where), only that the noise came from within the left side. 

Anyway, I plan to check it again in the morning.

 

The thread seems to have drifted quite far away from Ivanka's problem