Car Talk Letter Writer

To show you how Detroit thinks when deisgning stuff let me tell you the tale of my SUV. I bought a 2003 GMC Denali about 15 months ago. When spring of 2003 came to the flat-as-a-pool-table Eastern Shore there were a few foot deep puddles on some roads after heavy rainstorms and I occasionally love to splash through them. I did this in my very low slung Honda 94 Accord EX for years with no problems. Here I m in this high end 7000+ lb SUV, with big 17 inch wheels, 4WD etc. etc. What could some puddle splashing hurt?

After 2-3 puddles the Denali has what only be described as a vehicle heart attack. Bear in mind this is a huge vehicle that is touted as being a top end uber-SUV. The dash lights up like a Christmas tree, the speed slows down to a max 10- miles per hour and the vehicle bucks and wheezes. I am barely able to crawl into the GMC dealership 2 miles away.

As it happens the designers put the air intake right above the right wheel well. The splashing puddle got sucked into the air filter, saturated it and made the diagnostic systems go into shock, and the entire vehile put itself into “cripple mode”. There was a intake re-routing kit GM had designed for this “known problem” and it took the mechanic over 3 hours to install it (thank God it was done under warranty) .

Mactech, am I reading your post correctly that the puddle would have to be several feet deep to cause hydrolock? If so, I’m wondering why she would park there anyway. She’d have to get out and walk through several feet of water!

Well, assuming the air intake design of the Neon remained largely unchanged between '95 and '99 (my Neon was a '98), yes, my 98’s air intake system consisted of the aforementioned snorkel over the top of the engine, leading to the airbox, just above the top of the exhaust headers

considering that a CAI is a relatively cheap and easy way to gain up to 8-10 HP at the crank, it’s a popular upgrade

with the stock air intake, the puddle would have to be up to the top of the fender wheel well before the stock intake would suck in water

once again, all bets are off if she had a CAI, with a CAI a standard puddle has the potential to hydrolock the engine

another possibility for her engine failure could simply be having a hot engine suddenly submerged in a cold puddle, thermal stress could potentially crack the block…

http://modernperformance.com/dcx/neonfendermat1.jpg

that’s the engine layout of the first-gen Neon, the blue tube to the right is an Iceman CAI, the stock airbox layout has the snorkel across the engine, the air filter sitting above the exhaust header and a tube running from the airbox to the throttle body intake, the Iceman bypasses the convoluted and restrictive stock airbox and pipes cool air directly into the engine

http://modernperformance.com/dcx/95-99_aem2.jpg

the AEM CAI sits more generally where the stock airbox was, that’s how high the water would have had to be to hydrolock the engine

Modern’s Iceman page has a better group of closeup pics…
http://modernperformance.com/dcx/iceman.shtml

But it’s fun to drive through puddles.

I bet that’s the limit of her logic in this particular incident.

I will vouch for Oldsmobile Aleros if you are interested in puddle-driving. I rented one and it had no trouble with 6 inches of water, repeatedly. When it’s the bridges that are flooded (due to insanely bad design), you just don’t have much choice.

She’s in high school, right? She probly saw one of her classmates plow their daddy’s SUV right through the lake and figured she’d join right in. And if anything bad happened, her dad would just sue somebody.

I’ve always been told that if you are in a situation where you run into some deep water (whether by accident or what have you) to not let up on the gas,keep the throttle steady. Letting up is what can cause the engine to stall. At least that’s what I’ve been told.

Besides, it IS fun to drive through puddles!!!