ChronoJ1

iTrader: (2)

As some of you may have read my past posts, I have an over heating issue.

1. Car overheats when stationary, but when revved up temp. goes down.
2. When the water temp shoots to red, the heater is cold.
3. When I rev up and hear the sc's distinctive water dizzling sound, the water temp immediately goes down.

From these observations and reading many old threads, I thought I had a bad water pump. So I picked up a timing belt, idler pullies, and a water pump and went to this shop which was recommended by a local 350z owner.

I left the car with them for 3 days, and today I called them to see if I can pick the car up.
The mechanic says:
1. We are not sure what the problem is, and it seems there are many deep rooted problems.
2. It could be the radiator, as there is a large cold spot in the middle (which I cannot confirm by myself)
3. There was a trace amount of hydro-carbon in the coolent. It could be a blown head gasket. (which I cannot confirm)
4 It could be the water pump, since there is a little bit of moisture around it . (which I can't confirm visually unless I have a lift)
5. It could be the fan. (I tell him, I tested the fan with my hand and it runs strong) Really? Hmm.. I mean the fan is rotating above the normal speed. (ok...)

I asked him if he can narrow down the causes, and he mumbles. "The car has a really complex timing setup and it is hard take it apart, blah blah blah blah" He keeps on giving me all kinds of BS, and finally hands me a bill for 50 dollars. 50 dollars for confusing me. ha!


So, my question is.
Is he just afraid of getting his hands on the car and feeding me b.s. ?

When I rev up and hear the water drizzling (which means coolent is flowing), the temp goes immediately down to normal. When the heater is not working (which means coolent is not flowing through the heater core), the water temp skyrockets. From these observations, I still think it's the water pump. Could a blown head gasket cause these?

The bastard told me to go to the dealer, which I have no intention of doing. This car is worth $4000 at best, and I'm not willing to spend 1500 on fixing this crap.

Mikethe1st

He's actually saving you money. He checked for a blown headgasket which is a $50 test in itself. In order for him to diagnose the problem fully it would probably cost you another $500-1500 in a engine teardown just to lead to the conclusion that you need a new engine. He's not going to waste his time/energy/reputation just to have you mad at him and a non running motor in the end. So he sent you onto the dealer. I would, and most independant shops, would have done the exact same thing. Lexus mainanance isnt cheap. My pops just had the same problem with his cadillac, after about $2k in so called bs repairs, in the end it was a bad headgasket. So he spent another $10k to have a new motor put in. Its a suck *** situation but you gotta deal with it, 1gz time??

ChronoJ1

iTrader: (2)

He doesn't know if it's a blown head gasket. Have you read my description of how the overheating goes away?
He doesn't know WHAT the problem is. And to tell you the truth, I don't think he spent anytime on the car.

shaman

I think the best thing to do is to take it out and get everything warm. Stop the car and look for bubbling in the overflow tank. Check the radiator for cool spots. Remove your thermostat. Pop it into a pot with water and heat it up. See if it is opening. lastly, get your radiator cap tested. IF you cant build pressure, you can't keep your car cool.

ChronoJ1

iTrader: (2)

My car does that. It periodically spits out coolent over the tank. What does that mean?

O. L. T.

iTrader: (17)

The water pump was a good guess, but if the heater is not working AFTER manually opening the heater core control valve then the thermostat is hanging.

shaman

If it is doing this with the engine running, it means that pressure is getting into th coolant system. Usually means that you have a BHG from what I understand.

ChronoJ1

iTrader: (2)

^
Jesus christ....
If that is the case, I'll be ditching this car.
Not because I don't love it, but because it's too much money for what it is.

Any other speculations are appreciated.

PERRYinLA

Can't blame ya for that. Just today, another CL member IMed me that his dealer service advisor told him that the SC3/4's are "too old" for the people that are staffed right now.

I'd try removing the thermostat temporarily, if only to eliminate it as a potential problem, and to increase the flow.

Also please clarify. You said: "Car overheats when stationary, but when revved up temp. goes down." <- Is that while remaining stationary? Can the car keep normal temp when stopped as long as engine is revved?

ChronoJ1

iTrader: (2)

Correct.........

PERRYinLA

I'll give this a shot, but overheating problems are hard to diagnose remotely, so you sometimes look silly when the real problem is found.

If the car keeps its cool while stopped as long as engine is revved, I'd say that eliminates the fan, but everything else is in play. Also, if you have head gasket probs, it's only causing cooling problems under load.

The relevant differences between fast and slow RPMs is the water pump is spinning faster, as is the fan. So it's possible there is blockage somewhere in the system. Only by spinning faster does the water pump develop enough pressure to overcome whatever is impeding circulation.

Also a slight possibility, and you may have already read this in my other overheating posts, is a water pump that, because of corrosion or wear, has too much clearance between the housing and the impeller blade, allowing too much coolant to "slip" through the gap and decreasing the efficiency of the pump. This is not likely, or we'd have heard of this by now- when our pumps fail, it is usually at the bearing.

It is hard to check the head gasket and water pump without extensive disassembly. The only easy thing to check might be the radiator- get some various-sized hoses and hose clamps and use your garden hose to blast pressurized water through the intake and see how it exits the other end.

What would really help here are some infra-red goggles that show the hot and cool spots of the engine, hoses and radiator!

ChronoJ1

iTrader: (2)

Thanks so much Perry.
I am planning on replacing water pump and thermostat on monday, as they need replacement anyways. And while at that, I'll have the radiator checked. If that doesn't solve the problem, we'll know it's a BHG. Only then I'll consider dropping this car.

codetoad

iTrader: (2)

I'd say its a faulty water pump from what you described. Don't fear the worst yet... I doubt its a blown headgasket. There are telltale signs when the HG goes kaboom. If it was a sizeable headgasket leak into a cylinder (enough to cause it to overheat) you'd smell it in the exhaust, and you'd have a noticeable decrease in coolant. Your cars performance would be pretty rough as well. It's probably something small.. Keep it simple. Change out that water pump first before you get yourself worried over something its not.

VJ RC51

I had a stuck thermostat in my 1JZ when i first got it running.... it has a bypass so it can flow enough when running to keep it cool but slow speeds it would run hot and bubble out the tank. Took it out, ran perfect.

ChronoJ1

iTrader: (2)

OVERHEATING IS GONE!


Things replaced:
- Timing belt
- Idler Pullies
- Cam seals
- Thermostat
- Serpentine belt
- Coolent flush.

Costed me 1200 dollars total. 300 in parts 900 in labor.
(Yeah, it's expensive, but I just didn't want to run into a shop like the first one. So I went to this place where they fix classics/hotrods. A lot more expensive than the regular shops)
Although it was expensive, I'm just thankful that it wasn't a BHG.

Thanks for the advices guys.