Heavily Undersealed on MOT

[will.broad]

I have seen a car for sale but it had an advisory on the MOT for heavily undersealed, should I avoid this car?

[palacebear]

Presumably the MOT tester is covering himself (not in underseal ). As he's not permitted to dig large chunks of rust out of the car, I would assume he's implying that the amount of underseal is preventing him carrying out a visual inspection to his complete satisfaction, but that the inspection he has been able to make hasn't revealed any corrosion. If you're considering purchasing the car, you'll be faced with a similar dilemma as you shouldn't really be digging rust out of the car until you've bought it!

[Budgie]

I personally will not buy a car that has got any underseal on it what so ever. I've walked away from quite a few over the years that are undersealed as its a gamble as to what's it hiding / covering up!
and it's not the best substance to put on a well sorted car as it dries out and cracks allowing moisture to creep under the layers and rots away at the steel out of view and without the owner knowing until it's almost too late !

[ianmack]

I remember years ago being told by a tester that he had just refused to test a car with ‘half an inch of underseal all over the bottom’. Definitely something to be very wary about.

[The vast minority]

I had to give a traveller to the scrap man last year that had very thick underseal over all kinds of unpleasantness. The more I removed, the more I found. Even the crossmember was partially sculpted from the stuff and I grew very despondent with this.
My advice would be never buy any car with underseal thick enough to hide anything because it’s going to be hiding something.
I never will again.

[BrianHawley]

I tried to sell an old Escort many years ago that was in good shape, but I’d gone a bit overboard on the underseal. A lot of buyers were suspicious and I ended up taking most of it off before I got a sale.