Does it sound like the radiator is the problem?

What I've done so far (keep in mind I've just had the car for the past 7k miles; 130k now):

1) New fans
2) Did a manual coolant "flush" with distilled water
3) Bought new radiator cap
4) Have left the car running for a while multiple times with the cap off to bleed air out & refilled radiator to top.

The problem is that I overheat only when idling. Now at first you might think it's the fans not displacing enough air because once I start moving that hot air now has somewhere to go.

However, I just learned today that even if I'm in park and I just rev the engine a bit, the temp starts to go down. I even plugged my scanner in to monitor the coolant temp. With the needle steady approx halfway, the coolant temp is about 219F. Once it starts getting hot enough (while idling) it'll start climbing towards 230F. A quick rev restores it to about 220, but then the process continues.

Hypotheses:
1) Bad water pump
2) Bad t-stat
3) Restricted airflow between radiator & condenser.

Can I reliably cross out any of the above hypotheses before grabbing a new radiator?

 

Model year, coolant maintainece history, # of miles is essential for folks to give you a informed answer. First off drain the radiator and ensure a quick flow. If the flow is intermittent you have a clogged raditator or a partially clogged radiator.

 

If you look under his name, it tells you his model year lol

 

Agree about the drain some off and look for a good flow.

But, it ssounds like you water pump could be on its way out. I had the same sort of problem with a Acura a few years ago. The blades were partially detached and would spin better when revved.

 

Check for air flow blockage - make sure there is not any "junk" built up between the a/c condensor coil and the radiator. Then clean the radiator and a/c condensor fins by either flushing with water or blasting with compressed air in the reverse direction of the normal air flow. The best and most thorough way would be to take the radiator out to get the best access to the a/c condensor core but people have done "good enough" jobs with out removal by going to a self service car wash.

 

When you say overheating? How hot does it get? What is the gauge reading?
If the vehicle is in fact overheating, I would 1st check to see if the t-stat is opening by feeling both radiator hoses. If one hose feels cooler than the other, then you most likely have a stuck t-stat.

 

I'll have to agree with the above. Sounds like a water pump problem. That's the only thing that's related to revving the motor.

 

^ good point...try the tstat first why not...

 

What you did not mention was if your cooling fans are kicking on. If not, the coolent temp. sensor could be the fault. This is a common failure. If the fans are working the T-stat and water pump would be the next things to look at.

 

MerlotMax, yup both fans kick on, and both speeds work. But since it seems the temperature drops if I rev the engine a bit, which to me sounds like airflow isn't the problem.

I'm more leaning towards bad "coolant flow" where the main components/culprit are components that deal directly with the coolant (radiator, water pump, bad coolant, low coolant, partially clogged hoses, etc). I've been waiting for a "hot" day to do a "controlled" overheat since I did notice my coolant level wasn't at the top in the radiator. I really hope I don't have a coolant leak but it's possible I had a huge air bubble that finally was let out but I didn't refill coolant (after all, I did just install a new rad cap).

Today the outside temp was about 81F and while trying to "overheat" by idling for a while, the highest the coolant temperature would go to was 228F (as read by my OBD scanner)...which registers at a little above half on the gauge. Couldn't get it to keep going towards the red zone.

So I'm gonna try you guys' suggestion of doing a drain to watch how it consistent the flow is. I'm then gonna make sure I got a good water/coolant mix since all I did before was drain the radiator, fill with distilled water, drain, then put 100% coolant in.

And if I don't have enough problems already, I just noticed a super high pitched sound that seems to be related to vehicle speed (vs. engine speed)....aka either a wheel or brake problem. ugghh.

PS: The t-stat is opening, both hoses get hot.

 

i think you're only supposed to put at most 70% coolant and 30% water

 

A thermostat is a cheap and easy place to start. You should never have 100% anti-freeze or even 70% anti-freeze in your radiator. Anti-freeze doesn't help with cooling anyway, it just lowers the freezing point. Try pure water and something like Red Line Water Wetter for now. You can add some anti-freeze when the weather starts to get cooler.

 

When I flushed the system with distilled water, I never drained the block. I remember reading somewhere that if you did this, distilled water was in the block and you could just add 100% coolant to the radiator and the two would eventually mix giving a good stoichiometric ratio. But I'm doubting the efficiency of that now.

 

The 50/50 pre-diluted coolant works best

 

Yeah, got a lotta stuff planned for tomorrow/sunday:

1) drain/flush radiator & refill with correct water/coolant ratio (while at the same time taking note of how good it drains)
2) replace struts & mounts
3) replace shocks & mounts
4) replace inner & outer tie rods
5) change eng oil
6) drain/flush trans oil
7) siphon/refill power steering (trans oil)
8) install speedbleeders & flush brake fluid
9) inspect brakes & calipers

But based on my record, I'll probably only get to do 1/5/6/7.

 

If the radiator drains erratically, remove from car and lay it face down on the ground. Pour in some CLR (1/4 to 1/2 a bottle) and fill with water, and let sit for an hour. Then flush with the hose. If you notice chunks coming out, then you just fixed the problem. Rinse and repeat for good measure, since your car is going to have a good amount of downtime while you do more work. I've rescued a couple radiators this way.

 

Thanks for the suggestion, will definitely be doing this!

 

OK, seemed to have improved, but it's still overheating. I think I'm just gonna have to give into "the Koyo".

Going through the "12 main overheating causes" in the FSM, I've listed my "test results":

Blocked radiator
- not blocked
Blocked condenser
- not blocked
Blocked radiator grille
- not blocked
Blocked bumper
- not blocked
Coolant mixture
- 50/50
Coolant level
- always at MAX in reservoir & in radiator
Radiator cap
- new OEM
Coolant leaks
- none, coolant level always consistent after a long cooldown
Thermostat
- both hoses get hot
Cooling fan
- both operate & at both speeds
Combustion gas leak
- ?
Coolant temperature
- overheating so it can climb almost to 240 F
Coolant overflow to reservoir tank
- level in reservoir tank increases when hot
Coolant return from reservoir tank to radiator
- level in reservoir tank decreases when cooling down
Cylinder head
- ?
Cylinder block and pistons
- ?

Aside from the question marks (which means I have no idea how to check), that leaves clogged radiator and/or bad water pump. The main consensus is this though: the car only overheats when it's hot (like >80 deg F) and I'm idling/stop-n-go-traffic, alluding to insufficient coolant flow since a quick rev drops the temp back down. If I notice I'm starting to overheat, what I do is throw it in neutral and rev a little bit...needle instantly climbs to a touch below halfway.

A water pump replacement just looks scary.

 

i had this problem too. turned out to be one of the cooling fans didn't turn on. Since you said you replaced those, im assuming those are good.

when your car starts overheating, pop the hood and see if both fans are on. If they are on full blast, then its either a t-stat, water pump (unlikely), or a bad radiator.

in that case, just pop in a new rad for $150.

 

Yeah fans are on full blast...I even drive around with my hood popped. Fans are doing the best they can, but the coolant is just too hot.

Just ordered a Koyo. $140.

I currently have three big issues:
- overheating
- leaking oil
- bump steer/tramlining/etc...

Hopefully I can at least knock out 1/3.

 

ah still got the leaking oil problem huh? i guess replacing the drain plug didn't help huh? lol

but hopefully this new rad will solve your problems because its relatively easier than installing a new t-stat or waterpump.

 

Yeah still leaking, but everybody pointed to my lower oil pan if the drain plug/gasket didn't fix it. I'm just waiting for my week off of work to go at it because if I try to get the lower pan off & strip something, I'm SOL and I really need my car for work. But since I'll be off work, I'll have a whole week to try to fix it or have someone else try.

As of now, just monitoring my oil level has been "good enough".

Overheating: just revving a bit in neutral has been "good enough".

Unstable steering: just being very attentive has been "good enough".

Thing is, "good enough" ain't good enough for me, especially since I only got the car in March. I already made the conscientious decision to fix it up the best I can though, especially since I acquired the car for under 5.

 

New radiator is on the way. I'm gonna try to shoot a video of how my old radiator drains when I do the replacement. All things are really pointing to clogged radiator.

It's very possible that when I "flushed" it, it caused more harm than good, as the drained coolant & the reservoir tank did have deposits. We'll see come next week, unfortunately, it won't be as hot next week (mid 70s/low 80s) as it is this week (upper 80s/low 90s)...meaning it'll make it harder for me to rule out that the problem is actually fixed.

 

I'm going through the FSM and see one of the "poor heat transfer" reasons are failed water pump which could be caused by loose drive belts. I thought the pump was turned by the timing chain? Why would belts have anything to do with it?

 

I found a solution for my oil leak reading the forums here. It turned out to be the oil cooler gasket. Got it replaced about 4 month ago and so far no problem.
A parts guy at the dealership actually told me that this gasket is known for getting bad...

 

Thanks for the info m_maxxy...I just replaced my oil pan today but might have to do that o-ring too.

Installed the radiator today....snapped some shots.

My upper-radiator hose -> another hose -> bucket "contraption" to force all old crap out the block by filling radiator with 5 gallons of distilled water so that it ultimately exited out to the bucket. Thanks to Love_00_Max...http://forums.maxima.org/7139689-post11.html






My condenser fins are pretty bent towards the bottom.




Inside view of the new radiator:




Won't really know if I fixed it 'til we have a hot day.

 

So far, so good...today was 85F. The gauge needle doesn't do the "hover" thing it used to by floating from a-little-under-half to about-half (or rising from there towards the red zone); stayed locked-in at a-little-under-half no matter what. Looks like the radiator was a good fix. Only time will really tell though, especially since approaching the end of summer.