1998 Nissan Sentra Coolant Leak

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NETSFAN
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  • 1 POST
I have a 1998 Nissan Sentra with 78,000 miles. A few months ago I

noticed that my coolant reservoir was empty and I filled it up. Three

weeks later it was back to empty. Previous owner told me the car had

overheated on them a few months back. I went to my mechanic who told

me that my radiator cap was broken. Of course three weeks later I

found out it wasnt since I was still losing coolant. There are no

signs of external leaking and this time my mechanic told me it was an

internal leak and that the coolant is leaking but is being burned off.

Also he mentioned that it would not be worth it to fix so I should just

fill up the reservoir every few weeks. I bought Stop Leak powder and

put half into my radiator without any success. A few weeks after I did

that, I noticed that my coolant reservoir became very dirty and

contained some oil and I was still losing coolant. Should I put the

other half of the Stop Leak into the radiator? Will I be fine

continually refilling my coolant reservoir with coolant? What will

happen if I continue this pattern?
Jan 22, 2007 at 12:48 AM
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RASMATAZ
  • ✓Experienced Mechanic
  • 75,988 POSTS
[quote:1df46555cb="netsfan"]I have a 1998 Nissan Sentra with 78,000 miles. A few months ago I

noticed that my coolant reservoir was empty and I filled it up. Three

weeks later it was back to empty. Previous owner told me the car had

overheated on them a few months back. I went to my mechanic who told

me that my radiator cap was broken. Of course three weeks later I

found out it wasnt since I was still losing coolant. There are no

signs of external leaking and this time my mechanic told me it was an

internal leak and that the coolant is leaking but is being burned off.

Also he mentioned that it would not be worth it to fix so I should just

fill up the reservoir every few weeks. I bought Stop Leak powder and

put half into my radiator without any success. A few weeks after I did

that, I noticed that my coolant reservoir became very dirty and

contained some oil and I was still losing coolant. Should I put the

other half of the Stop Leak into the radiator? Will I be fine

continually refilling my coolant reservoir with coolant? What will

happen if I continue this pattern?[/quote:1df46555cb]


Test for a clogged-up radiator-if not might be the head gasket/head/block-if it is, use Thermagasket
Jan 22, 2007 at 4:56 AM
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JCROW
  • MEMBER
  • 13 POSTS
Oh wow... that bites... I don't know what 'internal' means... does that mean inside the engine as opposed to leaking out of a hose???

Well, here is all I got-- I was in Auto Zone looking at one of those info thing they got and they were advertising a pair of UV inducing goggles... if you put them on, in theory, you should be able to see any liquid that will show up under a black light (and coolant usually is glowy). So maybe you could find out where it is coming from and then it would be worth fixing... but I don't know if that really helps...
sorry.... good luck.
Jan 30, 2007 at 11:50 AM
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RASMATAZ
  • ✓Experienced Mechanic
  • 75,988 POSTS
Have it block and pressure tested-obvious your burning it inside this will take you to an internal engine leakage

Block test, when that blue color turns yellow meaning you have hydrocarbons-its an indication of a problem with the head/block/gas

Same as pressure test-when that needle fluctuates erratically-you face the same problex.
Jan 30, 2007 at 2:41 PM
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RSTEVE61
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  • 1 POST
Check oil usually at dipstick and through cap at rocker arms for water deposits or oil tha looks like a milkshake. Likely problems are: leaking cylinder head gasket or crack cylinder head or bore. If your lucky it loose cylinder head bolts or intake manifold gasket leaking or your timing cover is loose broken or cracked.

Hopefully this helps!
Feb 1, 2007 at 1:48 PM

Suggested Repair

Have the engine block-tested and the cooling system pressure-tested, and check the oil for a milky appearance or coolant deposits. A failed head gasket, cracked cylinder head, or cracked block is the likely cause; do not add more stop-leak or rely on repeatedly refilling the reservoir.

Conversation Summary

A 1998 Nissan Sentra with 78,000 miles was losing coolant with no visible external leak after a prior overheating incident. A mechanic suspected an internal leak and suggested only refilling the reservoir, but stop-leak did not help and oil later appeared in the dirty reservoir. Experts advised a radiator check, block test, and pressure test, plus inspection of the oil for coolant contamination. Likely causes include a leaking head gasket, cracked head or block, loose head bolts, an intake-manifold gasket leak, or a damaged timing cover.

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