Coolant hose busted

Zygrene · 30 June 2015

Hi all,

I'm looking to purchase my first 1991 NSX this week, and will get it inspected at an NSX specialist. Before I get his professional opinion on the car, I wanted to get some thoughts from current owners.

1) When I test drove the car a few weeks ago, a coolant hose busted but I didn't notice it until I pulled the car back into the owner's driveway. The test drive lasted about 15 min. There was blue/white smoke pouring out of the engine bay, and we saw that one of the larger hoses had busted. The owner then drove the car from his driveway back into his garage and later replaced the hoses and added "a couple of gallons" of 50/50 water/coolant back into the reservoir.

- What's the risk of any serious damage?

2) Timing belt and water pump have not been changed since 2008, about 11k miles ago.

- How urgent is it for me to get this done? Could I potentially wait a few months or is it risky?

Thanks in advance.

SarcasticaLy · 30 June 2015

7 years?? That's RIGHT about when I would replace it. I forget which NSX mechanic told me they recommend 6 years or 90,000 miles. I would get it done SOON. That's THE service on the NSX that you don't wanna mess with. Obviously, all the rest of the hoses need to be replaced. Id go ahead and replace EVERY single hose (even the one he replaced). With all that happened in that instance, I wouldn't be too worried about any damage but more about the history of maintenance and care. Good luck.

Old Guy · 30 June 2015

7 years is the guideline that Honda dealers in Canada seem to use for the time based limit on timing belts. If the car has not been tracked or subject to cold or hot extremes, you could probably let it slide a little bit. If the water pump was replaced in 2008, I would not view replacement as mandatory unless you are risk adverse.

Losing a couple of gallons of coolant on an all aluminum engine is not trivial. Mention that to you specialist and discuss the advisability of a cooling system pressure test and a compression test to check for possible head gasket damage.

bngl3rt · 30 June 2015

Zygrene said:
The owner then drove the car from his driveway back into his garage and later replaced the hoses and added "a couple of gallons" of 50/50 water/coolant back into the reservoir.

- What's the risk of any serious damage?

Severe. Also, Acura coolant is pre-mixed and doesn't require any water, and after a screw-up like that you don't just "refill" the system - it has to be properly bled to ensure there are no air bubbles, and preferably also pressure tested thereafter.

Zygrene · 30 June 2015

Ok, then I will plan to have the timing belt and water pump replaced ASAP.

As far as the coolant hose issue, how much should I expect to pay for a cooling system bleed, pressure test, and/or compression test?

Larry Bastanza · 30 June 2015

Do the comp test first. If that fails, I would move on, because you will need at least a top end engine rebuild.

Maybe $75-$100 for the comp test, but it varies........

Zygrene · 30 June 2015

Larry Bastanza said:
Do the comp test first. If that fails, I would move on, because you will need at least a top end engine rebuild.

Maybe $75-$100 for the comp test, but it varies........

Should I do a leakdown test or compression test? I got a quote for $229 on the leakdown, and was planning to split that cost with the seller.

The pre-purchase inspection is $168.

GraemeD · 30 June 2015

Zygrene said:
Should I do a leakdown test or compression test? I got a quote for $229 on the leakdown, and was planning to split that cost with the seller.

The pre-purchase inspection is $168.

IMO;
Do the compression test first, then the leak down (optional if the compression numbers are perfect) they both check the health of the combustion area, but can identify different issues.
Your PPI cost looks a little low, did they provide you with a list of what they are checking?

Zygrene · 30 June 2015

GraemeD said:
IMO;
Do the compression test first, then the leak down (optional if the compression numbers are perfect) they both check the health of the combustion area, but can identify different issues.
Your PPI cost looks a little low, did they provide you with a list of what they are checking?

If I do a compression test, isn't there still risk of the leakdown failing? Vs, if I do the leakdown test first and all is well, a compression test should be unnecessary?

I haven't gotten the checklist for the PPI, but the shop I'm going to is well known for servicing NSXs.

GraemeD · 30 June 2015

Zygrene said:
If I do a compression test, isn't there still risk of the leakdown failing? Vs, if I do the leakdown test first and all is well, a compression test should be unnecessary?

I haven't gotten the checklist for the PPI, but the shop I'm going to is well known for servicing NSXs.

a leak down will identify leaks and where they are. a compression test can identify if the cams are timed correctly relative front bank to rear bank. best bet is to do both.

good luck with the inspection and maybe the purchase.

Zygrene · 30 June 2015

GraemeD said:
a leak down will identify leaks and where they are. a compression test can identify if the cams are timed correctly relative front bank to rear bank. best bet is to do both.

good luck with the inspection and maybe the purchase.

Thanks.

In the interest of time, I may only be able to do one or the other. In this case, would it be advisable to do compression instead of leakdown? I read on a different forum that perfect compression numbers should be good enough. But your description makes the two tests sound independent.

GraemeD · 30 June 2015

They are not independent, one is looking at everything Static, and the other is dynamic. An extreme example would be a completely worn out intake camshaft, just barely opening the valve. a leak down would/could show perfect because the valve is closed at the time of the test. a compression test would show low because it can't pull enough air in to compress. subtle differences, but differences anyway, that is why I suggest doing both when evaluating an engine.

Larry Bastanza · 30 June 2015

I typically do a comp test first. If it fails I do a leakdown to diagnose the comp issue. In your case, if it fails, you should be done, JMO......

Zygrene · 30 June 2015

GraemeD said:
They are not independent, one is looking at everything Static, and the other is dynamic. An extreme example would be a completely worn out intake camshaft, just barely opening the valve. a leak down would/could show perfect because the valve is closed at the time of the test. a compression test would show low because it can't pull enough air in to compress. subtle differences, but differences anyway, that is why I suggest doing both when evaluating an engine.

Larry Bastanza said:
I typically do a comp test first. If it fails I do a leakdown to diagnose the comp issue. In your case, if it fails, you should be done, JMO......

Ok, then I'll do a compression test first. If it fails, and the seller is unwilling to cover the cost of any potential repairs, I will walk away.

- - - Updated - - -

I just got off the phone with 2 mechanics. They both told me the possibility of engine overheat could cause head gasket issues down the road, and a compression/leakdown test will not necessarily predict that. One mechanic also said I should check the ECU history to see if the check engine light came on when the hose burst.

Opinions?

- - - Updated - - -

So, interesting turn of events. Hill Top is now denying me service. The mechanic said he doesn't feel comfortable inspecting/testing the NSX, because he doesn't want me to come back to him with issues afterwards.

I called the Acura dealership in Burlingame and they agreed to do the compression/leakdown test, cooling system pressure test, and general PPI all for $250. Scheduled for Friday morning. Fingers crossed.

Old Guy · 1 July 2015

The mechanics are 100% correct. The engine may pass the compression & leak-down tests; however, there may be damage that could result in premature head gasket failure in a few months. Then again, it could be just fine.

If the engine fails the tests; better off negotiating a price cut than asking the owner to foot the cost of the repairs. The owner may be tempted to go cheap. If you do the repairs, you take the risk on the repair cost uncertainty; however, you have some degree of control over the quality of the repair. Its the better solution if you are anticipating long-term ownership.

If you are looking for the owner to indemnify you and cover the cost of a repair for some period of time (6 months?) after you take ownership, good luck with that. I know zip about US law; but, in Canada, even if you managed to write a legally valid agreement with that provision, the hassle of getting it enforced if the individual decided not to comply with the agreement would be too much effort. If the individual was a business or corporation with assets you would have better luck. Best to walk away from the deal if you are looking for that kind of indemnification.

Edit:

Others can comment; but, I think checking for an engine code is of little or no value. The OBD system is designed primarily to monitor things that affect emission performance. I don't even recall seeing a code for engine over temperature. That's why people call it a 'check engine light' as opposed to a 'stop the engine right now because it going to melt down' light. That said, if the head gasket is damaged it might throw some kind of mixture out of range code or a misfire code; however, if it was doing that I think there would be other evidence of a problem.

As a matter of curiosity, which hose failed?

Zygrene · 1 July 2015

Old Guy said:
The mechanics are 100% correct. The engine may pass the compression & leak-down tests; however, there may be damage that could result in premature head gasket failure in a few months. Then again, it could be just fine.

If the engine fails the tests; better off negotiating a price cut than asking the owner to foot the cost of the repairs. The owner may be tempted to go cheap. If you do the repairs, you take the risk on the repair cost uncertainty; however, you have some degree of control over the quality of the repair. Its the better solution if you are anticipating long-term ownership.

If you are looking for the owner to indemnify you and cover the cost of a repair for some period of time (6 months?) after you take ownership, good luck with that. I know zip about US law; but, in Canada, even if you managed to write a legally valid agreement with that provision, the hassle of getting it enforced if the individual decided not to comply with the agreement would be too much effort. If the individual was a business or corporation with assets you would have better luck. Best to walk away from the deal if you are looking for that kind of indemnification.

Edit:

Others can comment; but, I think checking for an engine code is of little or no value. The OBD system is designed primarily to monitor things that affect emission performance. I don't even recall seeing a code for engine over temperature. That's why people call it a 'check engine light' as opposed to a 'stop the engine right now because it going to melt down' light. That said, if the head gasket is damaged it might throw some kind of mixture out of range code or a misfire code; however, if it was doing that I think there would be other evidence of a problem.

As a matter of curiosity, which hose failed?

Excellent input, I really appreciate it. I am not going to hold the current owner liable if any damage occurs later down the road. That would be a complicated and foolish move on my part, and I'm sure he wouldn't agree to it anyway.

There are 2 possible scenarios. One scenario is clear to me: if the compression/leakdown test or coolant pressure test fails, I will ask for a price cut based on Acura's estimated cost of repairs. Otherwise I won't purchase the car.

I am only worried, ironically, if the tests all pass with no problem. This is the 2nd scenario. Then, I will be wary of the head gasket failing in the future. Is there any way I can get this checked out for signs of premature failure? I got one recommendation from a different forum:

"Also, the mechanic certainly can detect a blown head gasket. They have a tool that replaces the radiator cap which has little plastic balls in it. If there is a blown head gasket, exhaust gas will leak through the bad gasket and into the coolant system. Then, it flows into the tool and makes the little balls float."

- - - Updated - - -

Update: I called the Acura service department and they confirmed compression/leakdown/coolant tests and PPI are all included for the $250. They will also use a "sniffer" tool to detect exhaust gas in the cooling system for no extra charge. If I want, I can add an ECU diagnostic test for $160. I told them to schedule it for now, but only after the other tests have been completed/validated. Will the ECU test help me at all?

Old Guy · 2 July 2015

A $160 ECU diagnostic test sounds like a service tech plugging a code reader into the OBD port, downloading any error codes and then giving you a printed report. You could probably buy a code reader for less than $160 and do your own diagnostic. Better yet, find someone who owns one and borrow it. They almost seem to be as common as socket wrenches these days!

GraemeD · 2 July 2015

I believe it is a '91, OBD I.
Just jump the test connector and count the flashes of the check engine light.
lots of info here on the forum on how to do it.

Zygrene · 2 July 2015

Old Guy said:
A $160 ECU diagnostic test sounds like a service tech plugging a code reader into the OBD port, downloading any error codes and then giving you a printed report. You could probably buy a code reader for less than $160 and do your own diagnostic. Better yet, find someone who owns one and borrow it. They almost seem to be as common as socket wrenches these days!

True. I did this with my S2000 and my car before that, but they were both OBD2.

GraemeD said:
I believe it is a '91, OBD I.
Just jump the test connector and count the flashes of the check engine light.
lots of info here on the forum on how to do it.

I'll look into it. I'm leaning towards skipping this test if the others pass. If the others fail, I probably won't buy the car anyway.

Coolant hose busted

Similar threads