Hi! I've got a 2000 Nissan Xterra XE, 5 spd, 4WD, 3.3L V6 with 120,000 miles.
I'm chasing an overheating problem that won't go away. In addition to the overheat, I've noticed the odor of coolant after driving for a while but cannot find a leak.
A little over a year ago I began having problems with the engine temp spiking whenever I had to sit in traffic after being at normal operating temperature. However, I could get the temperature back to normal once I started moving again. I took it to the dealer who replaced the water pump, and the problem went away. (Feb 2006)
In July I was sitting in traffic and suddenly had the exact same problem again. Again, I could get it back down once I started moving. Had the cooling system flushed, and the problem went away (July 2006).
In November, in traffic again, the problem returned. Again, it went away at speed. Finally decided to start looking into it more on my own, and found the coolant was low. Added coolant, and the problem immediately stopped. (Nov 2006).
I should mention that the faint coolant odor was present even during the times it wasn't overheating.
Last week it started again. Adding more coolant did not immediately fix the problem. Also, I could not get the temperature back down by driving. Another difference is that this time the temperature gauge did not spike to the top. Instead it rose to about 3/4 and held there, slowly increasing at higher RPMs. I was able to get it to a local shop, and here is where we are:
a.) The coolant level was low, so that was remedied. They then diagnosed the problem as a worn out upper hose after finding seepage near the connection. On the way home, the engine again started to run hot after about 15 minutes of normal driving, but did not spike.
b.) They tested it again, and found it was running steadily at about 217 instead of 185. Replaced the thermostat. Again, 15 minutes into driving, it ran hot.
At this point we weren't sure what to do. They administered a block test (I believe checking pH of the coolant), but it had been changed/added enough that there may not have been enough evidence for a conclusive test.
c.) Today, replaced the lower hoses as we'd read that sometimes the collapse at higher speeds if they're weak. Mechanic tested, and she still gets hot.
d.) Replaced the fan clutch. Again, no effect.
They also visually watched the radiator flow, and do now *think* there is a blockage.
e.) The radiator cap was also replaced today.
- In the morning I can drive it most of the way to work (or the shop) without any overheating at all, as long as I stay under 55, which correlates to about 200 RPM in 5th. I do this with the heat on high for the most part. On the way home from the shop, I cannot control the heat as well, but the gauge does not spike as long as I'm under 2500.
- The coolant odor was still present as of this morning, before the lower hoses and cap were replaced. I'm assuming this is still present with the overheating issue.
ANY help you can provide is greatly appreciated. We're already down to 1 car, and THIS is the good one! (Ugh)
Thursday, March 1st, 2007 AT 2:34 PM