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Lost RESERVOIR cap; added coolant to RESERVOIR and not radiator; added wrong engine oil -

My little Nissan Versa has 1 different cap for its radiator, and another for its RESERVOIR. I was told by the Nissan dealer’s parts guy that aluminum foil would do-the-trick for the RESERVOIR cap. Does this sound accurate? Also I goofed again by adding coolant (with half water) to the RESERVOIR and not the radiator. I have an eye-dropper where I can squeeze out much of the coolant’s mixture. But my radiator still is lacking in coolant…at least I think it’s lacking. I stuck my finger down in its neck and came up empty.

Also,I mistakenly added one quart - just one - of 10W40 oil to the engine. The manual says 5W30 which was used when I had the oil changed a few months ago. The engine oil capacity is 3-1/8 quarts. Did I hurt the engine by adding this one quart on top of what was remaining since my last oil change? The dipstick registered next to nothing before I added the goof oil.
Thanks a lot.

No, foil will not do the trick. Cooling systems are pressurized. The foil will not allow pressure to build up, so the cooling system won’t work properly and you will overheat. Just buy a new cap from the dealership or an auto parts store. They’re cheap, and one from the junk yard will be who knows how old and may or may not hold pressure.

Your engine is potentially already in rough shape because you ran it low on oil. There’s a leak or a burn somewhere, so you need to keep a closer eye on the oil level from here on out. And you should try to figure out why you are losing oil. It could be as simple as a bad drain bolt washer which would be worth fixing.

You probably didn’t do any damage with the heavier weight oil yet, but you should do an oil change with the proper weight of oil right away. Don’t forget to replace the filter.

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You can’t even drive that car to the dealer to get a new radiator cap unless the dealer is around the corner. Take an Uber. Also, is the oil level at the full line on the dipstick now? If no, add the right oil until it is, then go get an oil change after.you put on a new radiator cap. If yes, put on a new radiator cap and go get an.oil change.

What year Versa?

If it has both a metal radiator cap and a plastic coolant reservoir cap, and you lost the plastic coolant reservoir cap, but still have the metal radiator cap properly installed, then yes, you can wrap the top of the coolant reservoir with aluminum foil and go buy a replacement. The plastic cap does not hold pressure.

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Sorry ShadowFax, I goofed (again.) It was the RESERVOIR cap and not the radiator. I was told by the Nissan dealer’s parts guy that aluminum foil would do-the-trick for the RESERVOIR cap. Does this sound accurate? Also I goofed again by adding coolant (with half water) to the RESERVOIR and not the radiator. I have an eye-dropper where I can squeeze out much of the coolant’s mixture. But my radiator still is lacking in coolant…at least I think it’s lacking. I stuck my finger down in its neck and came up empty.

Sorry old-mopar_guy I goofed (again) as it was the RESERVOIR and not the radiator cap. I was told by the Nissan dealer’s parts guy that aluminum foil would do-the-trick for the RESERVOIR cap. Does this sound accurate? Also I goofed again by adding coolant (with half water) to the RESERVOIR and not the radiator. I have an eye-dropper where I can squeeze out much of the coolant’s mixture. But my radiator still is lacking in coolant…at least I think it’s lacking. I stuck my finger down in its neck and came up empty. So I’m guessing I need to add more coolant to my radiator? Thanks again.

Awesome! That’s what the Nissan parts’ guy told me. Seeing as how I stuck my finger down the radiator’s neck and came up empty, I’m guessing I still need to add my coolant mixture to the radiator? Will it hurt to keep the reservoir somewhat full? (It’s maybe an inch from the top.) Thanks again.

You did not goof by adding coolant to the reservoir, do NOT remove the coolant from the reservoir. But DO also fill the radiator. After driving and getting the car fully up to tempurature, do not be surprised if you need to add more coolant after the engine fully cools, like overnight.

Why do you consider that a goof? If a vehicle has a reservoir, then that’s the way you’re suppose to add coolant. You can add to either one…but it’s safer to add o the reservoir.

If the reservoir is not under pressure, the aluminum foil will work. Fill your radiator with a 50/50 mix of coolant and water to the neck.

By the way, if you have to continually add coolant you have a leak that needs to be repaired.
You also need to check your oil every fill up or every week, which ever comes first.

The Nissan guy was right this time, but I’d caution you about listening to the guy behind the parts counter because they can give really bad advice. They overhear mechanics talking and they mistakenly think they understand what they hear and then pass on misinformation to customers.

Adding coolant to the reservoir tank should have worked Ok if the coolant in the radiator wasn’t too low, but it is not the best practice. If the radiator is a little low, when you operate the car, the coolant will expand pushing air out the radiator cap and into the reservoir where it will bubble to the top and be expelled. When you shut down, the coolant will contract and draw coolant from the reservoir into the radiator bringing up the level in the radiator. After a few cycles the radiator would be full and your reservoir would need some coolant added to it.

If there is too much air in the radiator, the cooling coolant may not create enough vacuum to draw coolant from the reservoir, in addition to your engine running hotter, so best practice is to fill the radiator (when cool, not hot unless absolutely necessary) and then fill the reservoir up to the cold fill line and not over (hot fill line if you are in a situation where you have to fill hot).

Never add coolant to an engine that is overheated (in the red). You must wait until it has cooled down because you risk cracking the block or head.

My recommendation to you right now is that you replace BOTH the radiator cap and the reservoir cap. It’s little money and I suspect that you really need both. If the radiator cap isn’t working properly, the potential damage involves big money.

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If your engine uses variable valve timing, suggest to correct this asap. VVT components are very sensitive to the oil viscosity, and can be expensive to repair.

As for the cooling system, it shouldn’t lose coolant faster than 1/2 cup every few months, if even that much. If your Versa is losing coolant faster than that, this also needs to be corrected, as that’ll eventually cause the engine to overheat and repairing that sort of damage can be even more expensive than the VVT. Don’t use foil to replace the expansion bottle cap. Either buy one from a dealership or good chance you can find a used one for cheap from a parts recycling place like Pick and Pull.

What parts will fail from using different oil?

If the OP had used the wrong oil at an oil change, I’d be concerned. But one quart doesn’t worry me.

From http://www.agcoauto.com/odfaq/index.php?p=default&cat=11

"Is it bad to put non-recommended oil in your car?

Yes, in modern vehicles, engine oil does far more than just lubricate the engine. There are variable cam timing mechanisms, hydraulic tensioners, displacement on demand and several other things that use engine oil. There are also many other factors, such as the affect of crankcase oil on catalytic converters, cold start lubrication, fuel mileage and so on to consider. Manufacturer’s take these and many other factors into account when specifying the proper engine oil. The vehicle manufacturer’s recommendation should be followed for best results."

People can write what ever the want to conjure up on the internet however some manufacture list an alternative oil viscosity and a wide range of viscosities that can be used when a vehicle owner leaves the jurisdiction of the EPA and there is no harm to the variable valve timing system.

I work on vehicles everyday that have variable valve timing and I have never seen a side affect from using the wrong oil. This is not the same as using the wrong oil in an engine with cylinder deactivation where the timing of the cylinder deactivation is critical for clean emissions.