Running thinner oil raised temps?
 

Hi guys, it's been a while since I have posted here, 2 jobs does that I guess :/.

Anyway, I finally got around to changing my oil after 9k miles (uhg) and I went from 5W-30 to 5W-20 and my engine temps went up 20F? I don't remember ever hitting 235F at night while driving home from work, and now I sit there for most of the drive. Also I run full synthetic if that means anything. I have some 5W-30 left of the same brand so I was considering putting some in to raise it but, I would like some input first.

The original Toyota recommended oil is 5w-30. Unless it was back spec'd, I would not use anything less than 0w-30 synthetic oil. (5w-30 if using dino) The 2nd number (30) should never be lower, especially if you are using grill blocks.

Your cooling system should be able to handle all sorts of variables, I haven't heard of different oils causing temp changes. It seems plausible, because increased friction would raise temps. But think about all your engine can do without temp fluctuation. If you decided to drive at double the normal RPM, or if it was 100 degrees outside. The temp still stays roughly the same, and should stay in a normal range especially on the highway with max radiator air flow.

Going to 0w20 hasn't changed my engine temperature. Maybe the oil is flowing faster and picking up more heat. Are your pistons oil spray cooled?

I wouldn't go to a 5w20 even if my engine was back spec'd. Stick with the 5w30, your engine will run as it did before and your fuel economy will still be the same as well.

I have run 5w20, 5w30, even 5w40 and never noticed any fuel economy changes that I could even hint at.

what is your climate like? last time I had an issue with temps that high i had a bad pressure cap. Come to find out, they are a typical wear item and cheap to replace. Try that first, if that doesn't help id suggest putting some Seafoam in the oil and changing back to the usual oil after a tank.

The reason your oil temp rises like that is that you need to use heavier oil or add an oil cooler. Turbo and forced induction owners need to watch oil temp to get a better gauge on engine load/wear.

Too warm temp will separate your oil and kill your engine.

After 9000 miles the old oil 5w30 could have been thinner than the new 5w20 oil.

Original radiator?

regards
Mech

1/3 of engine heat is removed via the engine oil, I would never go thinner on an older motor.

+1

If anything - evidence points that cooler oil cools the metal parts of the engine better than heavier oil. Flows easier, quicker and is able to move throughout the system better.

A temperature spike is never good.
Many years ago I ran 0w-30 oil in my camaro for a long time then one summer I switched to 10w-40 and saw a 10 to 15 degree temperature reduction and have ran 5w and 10w-40 ever since.

I agree, I would not run 5W-20 in anything higher milage even if speced for that oil.
Remember manufacturers recommend 0w-20 or 5w-20 for their benefit, not yours.

Cummins did a fuel economy test on their engines and found that there was only a 3% fuel economy difference between 15w-40 oil and 5w-20 oil. And only a 1% difference between 10w-30 and 5w-20 oils.
I posted a link to that study on here some where on another oil question post.

the extra heat came from somewhere.... either from more friction within the engine itself or the oil is absorbing more of the heat created by combustion....

if one were to have a consistent history of used oil analyses(sp?), then you could determine which pretty easily. if not, kind of guessing.

IMHO, this is discussion is too much based in theory and too little in practical knowledge.

As an engine gets older and after it has had more wear on it, it might benefit from using a heavier weight oil. Where (in what climate) does the OP live? That has a bearing on choosing a multi-viscosity oil that would be best for the climate involved. There is no "one size fits all" best solution.

When it comes to oil choice and oil viscosity, living in Alaska is different than living in Florida...

The age of the engine matters. And its operating enviornment matters. ;)

OP: ultimately, there may be another problem that is affecting your FE in coincidence with your recent oil change.

Thanks for the help guys. I'm sorry it took so long for me to reply but that's my life as it is now. Anyway, I figured out what the problem is, my rad fans refuse to kick on unless I turn on the AC. I know they used to kick on before but even unplugging the thing I did last time (the name of it escapes me) which forced them to come on doesn't do it anymore. I'm stumped and don't really have time to fix this. Sigh.

Also, I live in the high desert. 90+ degree summer days but the nights I know where it ran cooler it was within 5 degrees the same.

Also to answer a couple other things brought up...

My car only has 91k miles so I wouldn't consider the motor 'old' (please don't take that the wrong way, I'm just saying).

@Mech, Yea it's the original rad, but again, the car only has 91k original miles. It has seen 16k miles over 6 months though... (76,400 to 91,600 in 6 months).

Radiators are like arteries in humans, they clog up over time. An easy check is put your hand on the top and bottom radiator hoses. If the temp of both hoses is similar that indicates your radiator is not removing enough heat. The difference in temperature needs to be about 60 degrees. At the point where overheating occurs the grunge in your radiator has reached a critical point and the radiator should be replaced. You are there due to age, I'm surprized it is not leaking at almost 20 years age, and replacements are not that expensive.

The symptoms ususally occur in springtime when ambient temps are on the rise. The cooling fan issue needs to be resolved, or unplug the compressor and see if the fans come on with the compressor unplugged.

A decent low milegae car like yours can be destroyed by serious overheating and engine damage. I didn't think it was related to the change in oil viscosity alone. In fact I don't think the oil viscosity has anything to do with it , which is why I asked about the radiator. Radiator degradation is very common and the processis so gradual many people miss the symptoms and loose a good car to a $120 radiator.

I think your cooling fan temp sensor is bad as well if I understand your last post. Fix that and the radiator and SAVE that old Camry. Make sure the cooling system is properly bled to get rid of air pockets when you replace the radiator.

regards
Mech

I put 5W-20 blended with Lubromoly, a little 5W-30, and a bit of Marvel Mystery Oil in my 10W-30 spec 1ZZ-FE (the additives just make me feel good, snake oil). My reasoning is that my engine is not up to operating temperature over 70% of the time the engine is running (read: mostly cold starts and 1-2 mile trips) so using a 5W-20 means it'll be at the correct viscosity more of the time. If operating temp is noticably higher I'd be concerned though, I do notice higher oil consumption with 5W-20 which is mildly concerning.

Yes, that is strange. Been using Mobil 1 0w-20 all winter in my 1ZZ-FE with no consumption issues. How many miles on your engine?

On the high temp with different weight oil, If you have too much oil it gets whipped up and air bubbles don't pump. You run hot and the valves get chattery. Does not sound like your issue but I like talk . SC

Old Mechanic said:

Agreed. The oil viscosity is unrelated to the problem. ;)

Then you don't need a low viscosity oil. 10W-40 should work fine.

It's a 2000 with 142k miles, pre-2003 engines all had oil consumption issues though (which leads to blown precats and blown oil rings, very common cause of death). I've only had 3 different batches of oil in there but the oil consumption rate seems to be highly variable, the current mix is being consumed at about 1 quart per 1500 miles which is "acceptable" according to Toyota. Looking through the service logs that the previous owner gave me, it's probably been worse before; He went through 2 post-cat O2 sensors in 2 years, and I had to change the O2 sensors again shortly after buying the car. Exhaust pipes and sensors were coated in a thick layer of soot. When I bought the car the sump was nearly dry, the engine having burned over 1 quart per 1000 miles for 3000 miles.

Since I drive slowly and don't go much over 3000rpm most of the time it doesn't burn too much oil, but you can see puffs of smoke coming out the exhaust when the engine is revved to 4000 or higher. Coincidentally, the O2 sensor died on the fastest highway trip I ever took (70mph avg at 3700rpm).

Problem is I work 2 jobs and I work everyday... I don't have the time to go and get it fixed. I just need something I can do to get my fans to come on and stay on. At this point I don't care about MPG, I just need my car to last through the month so I can get a couple days off.

Anyway, to clarify more, when I used to unplug the greed plug (see pic below) the fans would kick on. Period, from the moment I started the car, to the moment I turned it off, now it doesn't do it. However, the fans DO kick on if I turn on the A/C but that obviously counteracts and cooling effect the rad fans would have due to the extra engine load of the A/C...

http://imageshack.com/a/img843/7713/ej9b.jpg

Balto, Some questions and considerations. How do you know the temperature is reaching 235? From your garage entry you have an added temperature gauge. Have you verified that against another method of measurement? If your gauge is electronic it only reports the information received from the sender. Bad sender? If you temperature is climbing that high at a steady 45 MPH you need to be looking at some other issue other than just fans.

As recommended in other threads you could try pulsing your heater or a continuous partial heat setting to reduce the temperature until you can get it repaired. Grill bock removed?

Yes I have an aftermarket gauge, I don't have any other way of knowing other then that sensor. I'll try it at 45MPH and see if it surpasses 210. Yes my grill block is removed. I hope my gauge isn't broken it costed me a lot to have the damn thing put in.

Ok well I just got to work. The upper rad hose is noticeably hotter then the lower, and even doing 45 I still see temps at 235. I can't even idle or it will go up to 250...

Make the AC fans run. At 250 that engine won't last long. Turn on the AC and set the temp to max warm. The compressor will not cycle much at all at max hot temp, but if the fans run continuously then it should get cooler. Also check the coolant level next time she is cold both the radiator itself and recovery bottle.

Not sure what to tell you with the temp difference in the radiator hoses and engine temp ashigh as 250.

1.Low coolant
2.Thermostat broken shut
3.Not enough antifreeze, pure water boiling
4.Not sure on a 95 Camry check online to see if the cooling system needs to be bled. Air pocket could be you primary problem.
5.It could be ahead gasket is giving out, have you lost coolant when it gets that hot?
Ride with the windows down and heat on max fresh air.

Bottom line is find away to make it run cooler or you will soon be faced with major engine work.

Of course all of this assumes your temp readings are correct. When I was working on cars daily I could hold my hand on a 180 degree top hose for about 5 seconds before I had to take it off or risk burning, at 250 my hand would be off in less than a second.

regards
Mech

Thank you for all your help mechanic, I do appreciate it. When she is cold I don't think there is any coolant in the little reservoir tank, I added distilled water a while back but it's gone now. As for the A/C, I have to drive to Long Beach (80 mile drive) so I'll let you know if it works. Will right back when I get there.

Sometimes folks pour radiator stop leak and the radiator veins get all clogged up. . Then new radiator time.


Also try running around with the rad cap half loose. It will steam a little but will burp the system good

Ok I just arrived. Doing as you said mechanic helped A LOT. I only saw 235 once or twice for a couple mins. Other then that I was running 210.

Top off the recovery bottle to the max level not minimum, it has marks. The next time check it cold and see if the level has dropped. I think you have a air pocket in the engine. Check it daily (the recovery bottle), but fill the radiator and the bottle when it is cold. You want to keep doing this until the level in the recovery bottle stays the same and the radiator is absolutely full when you removed the cap with the engine cold.

NEVER REMOVE THE CAP HOT OR YOU COULD BE SCARRED FOR LIFE!!!!!!!!!!

I would check it before your drive to work and after you get off work. If you keep the radiator absolutely full COLD, then your overheating should stop.

If you can keep the radiator absolutely full, the level in the recovery bottle will rise when the engine gets hot, and drop as it cools off. If the rad is full and the recovery bottle level stays the same when the engine is cold, you're good. If the level in the radiator stays full but the level in the recovery bottle keeps dropping over a few days, you have a leak somewhere.

I have seen people ignore this advice and fry an engine in a $10k car, that was not even paid for and now they need to spend another 5k to fix it and they were upside down before they fried the engine.

That's why I wont touch a repo, I'd rather buy it totalled.

Let me know what happens.

regards
Mech

Basically you are burping the air pocket out of the engine.

regards
Mech

Ok ok, can I use just Straight distilled water or pre-mixed stuff? I'm going to use my uncles car to get whatever is needed tomorrow morning.

Not knowing what percentage of antifreeze you already have in the system, if it was me I would put straight antifreeze in it for now. That way you are not possibly creating another problem. The boiling point of coolant depends on the mix percentage and the pressure cap to be working properly.

Mercedes service bulletins in 1982 stated that the coolant in their new cars would function properly up to 256 degrees. I never want to see my car come near that temperature and you have been very close. Your problem could be as simple as not enough anitfreeze in the mix.

Without knowing which is the case, I would err on the side of straight coolant (add no water). If you use water then you could lower the boiling point where it could boil, just because the mix was not a high enough percentage of antifreeze.
I think you came very close to loosing that engine and the jury is still out so to speak.
Spend a few bucks on pure antifreeze.

I used to save used anitfreeze at my shop so we could pour it in cars that had problems like yours, so we could properly diagnose the problem. I also had good relations with a superb radiator shop, who could diagnose and repair problems properly.

The crucial question right now is do you have a leak ? I have not added a drop of coolant to my Fiesta in almost two years. Where did your coolant go and what has to be
done to make it stop loosing or boiling out coolant? Just get it full cold, both rad and bottle. Then see if that level holds. If it does then drain and refill with 50-50 mix of distilled water and antifreeze or buy some premixed 50-50.

This has been going on a while most likely, and it has just reached the critical point.
Be patient with me and we can walk you through it like you had been working on cars for 30 years.

The level in the bottle will rise as the coolant heats up and expands. Take amagic marker and mark the level cold on the bottle. Check,check,check the radiator and bottle for at least a week, every day. It may take a while to get all the air out of the engine, but when you do the bottle level will rise when ho and drop as it cools off.

regards
Mech

Ok lemme try to respond to this and make some sense. I noticed the reservoir was completely empty about 2 months ago, so I grabbed some distilled water and filled it up. After that I cut my radiator hose to install the sensor for my Aftermarket gauge. I never added water after that. Maybe that was the start of the problem. Also, I don't think it has a leak, I park on concrete at work and home and never have seen anything but I'm not going to dismiss it just because my untrained eyes haven't seen it. I'll grab some Strait antifreeze tomorrow and see what happens.

I'm guessing you cut the top hose?

Absolutely use your uncle's car to get the antifreeze, then top the rad and bottle (at least 3/4 of the bottle) and drive it just enough to warmup. I'll bet your temp drops just from those actions.

Dont worry so much about responding to every post. it may take a few days to "burp" it. Absolutely watch for any leaks. I had one in my 99 Maxima. Drove it 400 miles and it never ran hot but I kept having to add coolant and finally spotted a leak at the top of the radiator, and replaced that day.

The coolant level was just low enough for it to not leak, it only leaked when I topped it up several times. I'll be here or in the ground.

regards
Mech

Oh, yeah, sure. It will "steam a little". :rolleyes:

Not good advice. The guy's got enough problems already without driving around with a loose radiator cap.

http://www.youtube.com/watch?v=owQcxSrKARA

This looks like a tech doing it with special tools. Not sure if it is the same year. I think you will be fine with my recommendations. Just get it warm enough for the temp gauge to read halfway. Do it a couple of times. When it runs cooler then drive it a little further.
You can't do it too much, unless the bottle coolant level stays the same. Run the heater on max heat to make sure you get any air out of the heater core as well.

DO NOT run it with the cap loose or removed. The air pocket could hit you with some very hot coolant or steam. Always check it cold. Wait at least 30 minutes at the very minimum, preferrably longer.

regards
Mech

My earlier post may have been overlooked, replace your pressure cap. The cooling systems are designed to operate when pressurized. No pressure=no cooling.

I had this problem a couple years ago, new thermostat, flushed the radiator, premium HOAT antifreeze and it was still running hot. Spent $6.99 on a new cap and temps never went over 210.

Less than $10 and less than a minute to replace.

As stated by old mech, DO NOT REMOVE THE CAP WHILE HOT!!!!