Corolla TS badly rusted earth

[pmf]

Found this on my low mileage 21 Corolla TS. It's situated near to Battery on nearside inner wing. No doubt this will cause issues sooner rather than later.

Dealer tells me not covered by warranty and Toyota CS not interested as they apparently rely on dealers opinion.

All other earth's and nearby connections are absolutely fine.

I'm going to have it sorted at a local auto electricians as I'm not waiting for it to cause me problems. 

[Mooly]

That looks quite bad taken in the context that neighbouring similar bolts are totally perfect. I could only speculate on cause, perhaps a 'faulty' bolt with no plating but even so its bad considering the age. Could there be some 'galvanic corrosion' due to a slightly high resistance somewhere in those connections.

It is bad enough to need proper attention I suspect. Toyota UK should see a close up those images.

One question/concern I would have is whether that earth connection can be safely dismantled without causing any issues due to what would then be a floating ground connection. I would say Toyota should be liable for that and to do a satisfactory restoration of that ground point. 

 

 

 

[TonyHSD]

This might be from salt on the roads or eventually acid from Battery leak if Battery is nearby. It dies look bad indeed. 

[pmf]

I did send Toyota UK a photo, but they weren't  willing to offer an opinion whether covered or not, leaving it to the dealer. They did suggest trying a different dealer but I would be several hours round trip for that. "Galvanic corrosion" is an interesting theory. 

There is no signs of Battery leak.  I don't think salt corrosion is an issue being under the bonnet on top of wing and wing liner is correctly in place and it is the only affected bit. The car has only done 18000 miles. 

I'm going to get it repaired at an auto electricians to ensure it is safely dismantled checked and cleaned. I am disappointed given only 2 years old. Basically I believe they are saying if the car breaks down or develops an obvious fault it's down to me as it's not covered by warranty if the earth is the issue. I'm not even sure what the 2 wires are earth's for, but I'm not willing to wait for the problem to emerge so will be getting it done asap.

[TonyHSD]

I would say it is from the salt indeed looking at the other two earth connections next to it, they will become the same in near future. They had signs of corrosion already. 
The problem with salt on the roads is that when melts or mix with rain water and the car used on motorways it’s like driving through sea.
Then if the car left to seat unused for sometime, no spring heavy rain motorway trips or jet wash to wash away this acidic accumulation it will start to eat away any untreated metal like bolts , nuts, black suspension parts. When we drive at speeds the water and dirt from the road gets into the engine bay everywhere with the air stream that goes through the radiators. Even well insulated cars like this one will let air together with water spray to enter and cover everything under bonnet. I have seen similar situations in cars that are well known for been corrosion resistant as early as 3 years old. My car has one bolt on the side engine mount rusted prematurely and some hoses clips as a salt on the roads. I drive a lot on motorways during winter salty times and wash the engine every year plus the spring rain helps a lot, but the car was previously a low miles example and the rust was already there. 

[Red_Corolla]

At first I thought the coating on the bolt might be defective, but the corrosion has also gone through the tin plating on the cable lug and started attacking the copper, so that would suggest some sort of external influence, but I'm at a loss to explain why the damage is isolated to just that one connection point.

Checked the same terminal on my own '21 model and it's completely unscathed. Mine has the fusebox behind this terminal rather than the Battery because it's the 2.0.

[flash22]

Disconnect the Battery, unbolt the terminal, clean it with brush or scotchbrite bolt it back up and coat it with a spray or grease

[pmf]

Mine is the 1.8l. I expect all  components in any way exposed to our UK climate/atmosphere to show signs of ageing, which the other earth's are, but they are fully serviceable and will be for sometime. However not to the extent we're seeing on that earth. The car doesn't go on a motorway that often and rarely in winter. 

Salt corrosion may be an aggravating factor but it must have been a very poor quality bolt, which is not even subject to wear and tear damaging any original protection.

Although, I'm more than capable of removing a bolt,on this occasion I'm going to let the auto electrician do it as I don't like the look/condition of the wire connectors. They can snip, solder and rejoin if needed, but I will definitely be giving it a spray of grease. Thanks.

[AisinW]

pressure wash the underbody everytime we have salty roads days

[Metalown]

On 9/1/2023 at 2:55 AM, AisinW said:

pressure wash the underbody everytime we have salty roads days

Toyota Corolla hybrid manual says "Do not wash the underside of the vehicle using a high pressure car washer." Are you sure pressure wash the underbody is going to be fine?

[TonyHSD]

18 minutes ago, Metalown said:

Toyota Corolla hybrid manual says "Do not wash the underside of the vehicle using a high pressure car washer." Are you sure pressure wash the underbody is going to be fine?

It will be ok if done correctly. 
I personally spray with the jet wash nozzle under side of the car as much as I can every time I wash during the winter season. I do also at least once a year engine bay jet wash and I never had any issues. 
Correct way is to spray from distance minimum 30cm and keep moving the spray, do not hold too close or at one point for too long. Avoid electronics and wire harness been close to the jet.
These are the important steps. Water spray pattern under high pressure and close proximity can become like a cutter. There is a risk of cutting cables, pill off corrosion protection, paint work etc. 

A super simple way and effective is to use garden hose spray nozzle with extension and turn it upside and pull under the car and go all around, select shower function or spray and with minimal pressure can wash the whole undercarriage without problem. 
When we are  driving on motorways at speeds in heavy rain for example  it is similar for the car to jet wash., more water less pressure though. 👍
 

[AisinW]

The automatic carwash tunnel will always wash the underbody, and it is fine.  If you do it on your own, don't spray areas where there are electronics and connectors. If you look under the car, there are no connectors at the bottom of the car.

A pressure washer is ideal to remove salts and sands. If there is no salts, the rust will never form that fast.  

We pressure wash the suspension, wheel well, bottom of radiator, axles, and brakes. Those areas will rust and are covered by salt. 

[Tomv]

I prefer washing with garden hose. IMHO, jet washing can push the salt to places, where it wouldn’t normally get.

[AisinW]

Garden hose is enough for body and outside parts. Not enough to remove mud and dirt that keep the moistures in.  

Salt but dry is fine, salt+water+mud is the problem.  As long as the hose is enough to remove mud, thats good.