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Old 7th November 2013, 06:20   #16
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Is this the first thing to get damaged in the underbody? Could there be any other part which is damaged and leaking oil?

I mean my car hit a rock underneath and I get down and see black muddy oil substance leaking from underneath the car, is there a way to know what is this which is leaking or I can be sure it's cracked sump only ? I think petrol tank doesn't get damaged so easily to start leaking.

Also on the rainy day I meant that there would be enough of water pouring down from up above, will it be possible to find out the oil leakage in that case.
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Old 7th November 2013, 08:00   #17
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Default Re: Underbody Hit & Cracked Sump : Implications, Vulnerabilities, Responsibilities

Good thread and a very important one especially for folks who travel a lot or drive in Bangalore

I would tackle this issue in two ways. 1) If I travel inter state a lot then I would be wise enough to get a sump plate fixed even though it means lowering the gc by a few cms. I am sure most of the cars have the provision. 2) If I mostly travel inside city I would drive patiently over bad patches but if I am very unlucky and get a underbody hit then I would follow what SS has informed in the first post.

I think knowing the underbody of your car is very important as it will help tackle situations where a hit is innevitable.
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Old 7th November 2013, 09:09   #18
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Default Re: Underbody Hit & Cracked Sump : Implications, Vulnerabilities, Responsibilities

Quite informative thread.Is there any way we can install bash plates for cars like the swift?About the oil pressure indication light,can we install oil pressure gauges like the ones we had in the old ambassadors?I am sure we can keep a tab on the oil pressure more effectively with a gauge.
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Old 7th November 2013, 09:13   #19
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Default Re: Underbody Hit & Cracked Sump : Implications, Vulnerabilities, Responsibilities

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Originally Posted by abirnale View Post
And another one - while running on under construction road, the stones that gets tossed under belly due to mediocre speeds or other vehicles (stones of size say 5-7cms in width) can cause similar damage? Often in the under construction roads, trucks ply beside the cars and such stones get tossed up. Rare but if its underbelly, it should be fine I guess as the speeds will be relatively slow?
Small stones falling from a truck can also cause the same harm. Don't underestimate small stones.

http://www.team-bhp.com/forum/techni...uild-cost.html

Last edited by Eddy : 7th November 2013 at 22:23.
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Old 7th November 2013, 09:29   #20
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Plus one ,please stop and remove stones from the road when ever possible ,it also impacts two wheelers
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Old 7th November 2013, 10:03   #21
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Default Re: Underbody Hit & Cracked Sump : Implications, Vulnerabilities, Responsibilities

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Originally Posted by tsk1979 View Post
Why is this wrong.
In case of major damage to sump with engine oil flowing out at speed you are right.
However, if you can patch up the sump so that its only 1-2 drops falling out at a time, you can top up the car, and drive for a 100km or so.
Think of it as a car which is leaking some oil. As long as there is enough oil available, its fine.
That said, a rock hit at speed will cause major damage, not small patch damage unless the under sump skid plate has taken the brunt of the impact.
Good point reg what you said in bold - that may be the case for some - the sump is bent but not broken - there's no oil leakage but the oil strainer may be bent or broken (leading to a choked off oil supply that can destroy the engine in a matter of minutes).

Quote:
Originally Posted by dhanushs View Post
IMO, In this case, the most important thing to follow while driving is to keep a keen eye on the instrument console, for the oil pressure gauge, or the oil warning light. Without which most people end up with a bust engine.

Not really. There is no need for synthetic oils to run short intervals. Only the correct or atleast near-correct grade for ~50-100 or so kilometers, by which hopefully, you can find a patch up garage (Removing/replacing/repairing the crank-case is very easy) and a proper oil. IMO, most turbos should survive.

And, I'd advice not to revv the engine really high in this interval, and to baby it. Load is OK, but rpms = absolute NO.
Agree on the precautions fully! Rest detailed below. btw, would your logic work with a VGT? a FGT i can understand - it won't spool up if you cruise at low RPMs. Not so sure about a VGT.

Quote:
Originally Posted by SS-Traveller View Post
Oh, come on, Hitanshu. For a 100 km, any (genuine) oil of whatever grade will keep your engine intact - provided the damage hasn't occurred already after the leak. I'd think Tanveer and Dhanush have responded to your opinion adequately - thank you both for explaining this.
Folks,

I think we are talking about two different things - a (relatively benign) pinhole leak versus a fairly solid impact that may break the oil strainer (if that is the word).

In my car's case - the impact was severe enough that the RED oil low light came on and I knew the damage was done (but thankfully only the TC was cooked). But as I have been told by multiple trustworthy folks (staff from Apra, my old MASS), sometimes the jolt may not break the sump but may result in the oil strainer getting bent or broken - which may choke off oil supply. That is something which may not be apparent right upfront (till the check engine light comes on - by when the damage has occured).

I would much rather suggest a few thousand in towing, than risk further damage - if it is in the window where the strainer has broken but the engine was shutdown in time to avert turbo / engine failure. The choice is an individual choice - I would just say it is not black or white.

Of course - I may be wrong, and it may so happen that for CRDi engines, the turbo RPM is so high that it fails almost immediately if the strainer breaks. It may not be so for NA petrols. What are you folks' thoughts on that aspect?

Let me ask a different question - has anyone here driven a car (esp a turbo diesel) 100km after a sump hit with a pinhole leak (sealed by m-seal or whatever else) to a service center? 50km? 20km?

Quote:
Originally Posted by SS-Traveller View Post
Once again, I'd think this is a bit far-fetched - choosing a new car based on TC cost is probably the last thing I'd do, in anticipation of an engine burnout event.
Different strokes for different folks. I have paid for replacement turbochargers thrice (maybe I was a fool two out of those times, but still). It is far-fetched for you, but it is a bitter memory for me. hence, its a *side* recommendation I would share with folks.
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Old 7th November 2013, 11:46   #22
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Default Re: Underbody Hit & Cracked Sump : Implications, Vulnerabilities, Responsibilities

This is very informative. I go for long drives a lot and never thought this will happen. I travel alone most of the times and this is scary.
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Old 7th November 2013, 13:14   #23
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Default Re: Underbody Hit & Cracked Sump : Implications, Vulnerabilities, Responsibilities

Quote:
Originally Posted by acidkill View Post
So which cars / SUV, according to you, protect the sump plate the best?
Not for me to point out specific cars, but any with substantial ground clearance below the sump (IMO >170-180mm), and / or a steel sump guard, should be good.
Quote:
Originally Posted by tanwaramit View Post
Is this the first thing to get damaged in the underbody? Could there be any other part which is damaged and leaking oil?

I mean my car hit a rock underneath and I get down and see black muddy oil substance leaking from underneath the car, is there a way to know what is this which is leaking or I can be sure it's cracked sump only ? I think petrol tank doesn't get damaged so easily to start leaking.

Also on the rainy day I meant that there would be enough of water pouring down from up above, will it be possible to find out the oil leakage in that case.
Engine oil looks, feels and smells quite different from diesel or petrol. And even if it rains, it usually doesn't under a car.

Quote:
Originally Posted by rakesh_r View Post
Quite informative thread.Is there any way we can install bash plates for cars like the swift?About the oil pressure indication light,can we install oil pressure gauges like the ones we had in the old ambassadors?I am sure we can keep a tab on the oil pressure more effectively with a gauge.
Bash plates - yes, can be installed. Check Sudev's Grand Vitara ownership thread for details about installation of custom-made underbody protection plate.

Oil pressure gauge - yes, again, can be installed easily. Only issue IMO would be where to place the meter on the dash. And how many folks keep an eye on all the meters?

Here's an estimate for engine repair of a Chevy Beat TCDi, after it took an underbody hit and lost engine oil in Kolkata...

Name:  Beat bill.jpg
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All 3 concerned parties - GM, the dealer (Longia Motors) and the insurance company (Bharti AXA) - are playing 'pass the parcel', and nothing has been done to repair the car in the last 1 month, because the owner (a BHPian) refuses to foot the whole bill.

Last edited by SS-Traveller : 7th November 2013 at 13:16.
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Old 7th November 2013, 13:27   #24
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Default Re: Underbody Hit & Cracked Sump : Implications, Vulnerabilities, Responsibilities

Quote:
Originally Posted by SS-Traveller View Post
Oil pressure gauge - yes, again, can be installed easily. Only issue IMO would be where to place the meter on the dash. And how many folks keep an eye on all the meters?
Very True, but for people who are interested to dig deeper, some OBD scanners show temperatures of coolant, oil etc. So may be its worth investing into the compatible OBD scanner and a smartphone that helps do many things. The usual car dashboard has lights to indicate various things but as soon as you know you have hit something and there is no visual trace underbody, it may be a good idea to pull your OBD scanner app, run it for any clues. This should work all the time come rain or sun.
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Old 7th November 2013, 16:24   #25
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Default Re: Underbody Hit & Cracked Sump : Implications, Vulnerabilities, Responsibilities

Quote:
Originally Posted by SS-Traveller View Post
The following list is by no means comprehensive, but points out some of the cars that are prone to taking underbody hits and breaking their sumps when negotiating not-too-big rocks or bumps on the road.
Quote:
Originally Posted by SS-Traveller View Post
Not for me to point out specific cars, but any with substantial ground clearance below the sump (IMO >170-180mm), and / or a steel sump guard, should be good.
I don't understand why have you included the humble punto into your list of vulnerable cars. The strong underbody engine protection plate, is amongst the better engineered parts of a punto. This plate is quite thick and heavy, and am sure you will find a lot lesser number of puntos in a garage with a busted sump, than any other hatchback/sedan.
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Old 7th November 2013, 16:40   #26
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Default Re: Underbody Hit & Cracked Sump : Implications, Vulnerabilities, Responsibilities

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Originally Posted by chaudh2s View Post
I don't understand why have you included the humble punto into your list of vulnerable cars. The strong underbody engine protection plate, is amongst the better engineered parts of a punto. This plate is quite thick and heavy, and am sure you will find a lot lesser number of puntos in a garage with a busted sump, than any other hatchback/sedan.

I request the link to punto be remove from the post as in that thread what actually happened is inconclusive.
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Old 7th November 2013, 17:16   #27
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Default Re: Underbody Hit & Cracked Sump : Implications, Vulnerabilities, Responsibilities

Quote:
Originally Posted by SS-Traveller View Post
Once the damage is done

STOP THE CAR!
Do not accelerate. Try to shift to neutral as quickly as possible, turn off the engine (but do not pull out the ignition key), and coast to a stop. Get under the car and assess the extent of damage. If there is any oil leak, do not attempt to start the engine again until the leak is fixed and the lost oil topped up.
I think its still better to watch out, brake hard to pull over and then turn off the ignition immediately instead of doing it on the run - Too risky as some might panic even more with brake and steering feedback going hard once the ignition is turned off.

It could be different if that's a open highway with none besides/behind.

Adding to what SS-Traveller has said, I would say:
While its being fixed temporarily (With Warning Triangle kept at the rear), Let the rest of the passengers stay away from your vehicle far away from there. Having seen many vehicles hit while parked roadside, I would say its risky to be in or nearer. But don't try to start the car and park it aside just to save it, you could actually damage more.

Quote:
Small cracks or holes on the sump can be plugged temporarily using one of the following:
  • Epoxy resin putty (e.g. M-Seal, QuikSteel, Loctite)
  • A mix of carbolic soap (e.g. Lifebuoy) and sugar crystals
  • Chewing gum (not very effective)
Thanks!

Quote:
Top up with ANY engine oil available at the nearest petrol pump or automobile spares shop - there is no need to be finicky. Even if it is a monograde mineral oil and not your favourite multigrade synthetic oil, it will still lubricate your engine well enough to let you drive to the next service station without your engine self-destructing.
+1

Last edited by ganesc : 7th November 2013 at 17:19.
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Old 7th November 2013, 17:38   #28
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Default Re: Underbody Hit & Cracked Sump : Implications, Vulnerabilities, Responsibilities

Quote:
Originally Posted by chaudh2s View Post
I don't understand why have you included the humble punto into your list of vulnerable cars.
Because someone has reported a cracked sump for his Punto in a thread, to which I have linked. Do all models of the Punto come with a sump guard?

Last edited by SS-Traveller : 7th November 2013 at 17:39.
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Old 7th November 2013, 18:28   #29
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Default Re: Underbody Hit & Cracked Sump : Implications, Vulnerabilities, Responsibilities

Quote:
Originally Posted by SS-Traveller View Post
So what can be done to minimize your chances of getting a cracked sump, and even worse, a seized engine?

When choosing a car to buy
Check below the car from the front and rear ends to determine which are the lowermost points, and how close they are to the ground. If you cannot identify any component, and think it is closer to the ground than the thickness of 2 bricks placed one over the other, get someone knowledgeable to check and determine what it is. Look for the presence of a engine protection plate, made of steel, that prevents the sump from being punctured or cracked.

The underside of the sump is the most vulnerable, and so is the gearbox and differential. Drain nuts on the sump/gearbox/differential are especially vulnerable if they are positioned at the lowermost point and are unprotected. Certain components of the suspension can be pretty tough and survive heavy knocks, even if they hit a stone on the road while driving.
[u][b]

FINAL WARNING: Rocks on the road can substantially lighten your pocket.
It would be useful to know which hatches & sedans have the best protection in terms of ground clearance and steel protection plate. I think this could also be one of the factors that tip the deal in favour of a vehicle. I'm hoping someone already has the data.
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Old 7th November 2013, 19:01   #30
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Default Re: Underbody Hit & Cracked Sump : Implications, Vulnerabilities, Responsibilities

Quote:
Originally Posted by tanwaramit View Post
... is there a way to know what is this which is leaking or I can be sure it's cracked sump only ?..
Gear oil smells funny, brake oil is will not be dark, petrol and diesel can be smelled, and engine oil will mostly be black (diesels) and dark petrols.
Quote:
Originally Posted by phamilyman View Post
Agree on the precautions fully! Rest detailed below. btw, would your logic work with a VGT? a FGT i can understand - it won't spool up if you cruise at low RPMs. Not so sure about a VGT.
Hi,
I meant, there is no harm in running with top up oil. Since, the turbo rpm will be different at different engine speeds, as a precaution its always good to maintain low rpms, VGT or FGT.
Quote:
... sometimes the jolt may not break the sump but may result in the oil strainer getting bent or broken - which may choke off oil supply. That is something which may not be apparent right upfront (till the check engine light comes on - by when the damage has occured)...
If the oil pressure goes down below harmful levels, the light should come up immediately, and ~20-30 seconds later, damage starts to happen, and a kilometer later, your bearings will be shot, after which the engine will seize.
Quote:
The choice is an individual choice - I would just say it is not black or white.
Agreed, but, I'd say whats being discussed here, ie, driving further, is a get-me-outta-here with minimal damage technique, rather than drive-on..
Quote:
Originally Posted by SS-Traveller View Post
The oil pressure indicator light is there in all cars. But depending on that to light up means there's got to be almost complete loss of oil pressure in the gallery. Well before that, components like crankshaft bearings, which depend on splash lubrication, would have run dry, with resultant damage and expense. Therefore, after an oil sump hit, it's best to check as early as possible if the car is losing oil.
Agreed, you should definitely get down and check for visible damage, and oil leaks. But, my comment was that you should keep an eye on the console, in any case. Make it a habit. In this particular, 'Underbody Hit' case, oil might not leak, but oil pump might get damaged in some instances, rendering oil pressure zero. Hence, I was asking to make it a habit to keep a keep eye on the console.

----------------------------------------------------------

That said: I'd advise a couple of things for people driving long distances and in broken roads.
  • Get yourself a sump guard made, if not present.
  • Carry a couple of liters of top up engine oil. It should be enough to get you out of a bad situation.
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