Questions and Answers

Nissan Coolant Loss Q. Hi Vince, Currently, my truck has coolant loss problem. Six months ago, my truck has coolant leaked into oil pan. So, I have the auto shop replaced head gasket, surfaced header surface, re-sealed timing cover, new radiator, new thermostat, new radiator cap, the water pump still in good condition.

The following condition appeared to be normal on my truck: the engine rpm, temperature, exhaust color, exhaust odor, oil color, coolant level in reservoir, coolant color, However, the coolant level in radiator is always dropped below the radiator neck and some time exposed the radiator core. I always have fill the up the radiator. The coolant level in the reservoir is always remain at the same level.

I noticed the coolant would overflow from the reservoir during the driving and after. I think the coolant loss by overflow through the coolant reservoir and coolant not able to return to the radiator. Please help.

Vehicle: 1990 Nissan pick up truck, 4 cylinder KA24E, 5 speeds, electronic fuel injection, 2 WD, no power steering, no A/C, 158,000 miles.

Thanks,
Jeffrey

A. It appears to me that they put the wrong radiator cap on. In your cooling system there is a small valve in the cap that opens with vacuum in the cooling system. As the coolant cools, it contracts forming a vacuum in the cooling system. The valve opens and the vacuum draws coolant from the reserve tank into the cooling system keeping it full.

When you fill the radiator and the coolant gets hot, it expands and it goes into the reserve tank, causing the symptom you describe. But it is not being drawn back in. I would go to a Nissan dealer and get a new radiator cap and put it on. That should solve your problem.

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