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  #16  
Old 03-23-2014, 02:36 PM
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stiguy stiguy is offline
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Re: Strange over heating

Thanks for your input!
I do know that the temp sensor is working correctly because when it reads in the red the coolant is boiling out the system.

Now this bleeder valve I have not heard of that I'll have to look it up.

I have not chemically flushed the rad yet. Going to take the rad to a shop and have them power flush it. They said they can tell if it's plugged by doing the flush.
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#1 1994 Ls ebony parts car-rip
#2 1994 L laguna blue - sold
#3 1992 Lsi pearl white - sold
#4 1992 Lsi pearl white -Ate two engines - Rip
#5 1994 L Laguna Blue fwd - Now Awd and manual - 03 wrx 5mt - 18's stern warp st4s - totaled hit a tree
#6 1992 Lsi custom orange parts car
#7 1992 Lsi green 4.44 swap. Currently for sale
#8 1992 Lsi custom pearl white. Project car... sold
#9 1992 Teal 4.44 swapped... sold
#10 1995 Laguna Blue. Sti 19 wheels,
#11 1994 Laguna Blue. Came with #10 engine and trans are out but plan to put it back on the road. Willing to sell it at any time! 😂
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  #17  
Old 03-23-2014, 05:45 PM
Chucksta Chucksta is offline
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Re: Strange over heating

NiftySVX and Tapani both told me to make sure that the t-stat was in the right way up. Just from their postings to me on other things, I know to listen when they speak. As I said, my automotive training is "dated" to say the least. As I'm rapidly finding out, there's a lot of things about an SVX that are particular and unique to the vehicle. What is in the FSM, is accurate, from an engineer's point of view. What is in the heads of the members here, from a standpoint of training and practical experience, is priceless. For example, the FSM says the brake band adjustment requires basically dropping the trans.. nope... From the info on this site, it can be done by blind feel in ten minutes. It's a *****.. but not nearly as big a ***** as dropping the tranny.

Nipple on the bottom? What's the issue? Gravity! Air can't get past it and rise easily to where it can be passed past the rad cap and into the overflow reservoir.

Luke... trust the force.. trust in the force...
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  #18  
Old 03-23-2014, 10:17 PM
Tapani Tapani is offline
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Re: Strange over heating

You do have all the bypass lines connected as they should? Heater and the TB too? And the hoses are not kinked? These provide the signal for the thermostat to open.

And the thermostat you have is an OEM Subaru part, yes?

Wen the engine starts to overheat is the lower rad hose cold or almost as hot as the upper one?

And your fans do come on as they sould when the ECU tells them to - even w/o the AC on?

It is funny that the engine boils at low loads (only?).

My HG leak was so small it could be noticed only on track days.

I could hear slight bubbling in the reservoir way before the flash boil. I could do two laps and then take it easy and it would just bubble :-).

The rad gas test went green only after a few uphill WOT spurts in first gear. Nothing after "normal" driving.

Proved to be HGs and all is well after the engine overhaul.

If you have the Ecutuner or Evoscan you can monitor what's going on. If I recall correctly the temp gauge needle started to move from the "normal" position at 103 degrees C. That's high :-). The highs during flash boiling were 112-115 degrees C.

The Subaru cooling system is carefully balanced and all needs to be in good condition for it to work as designed (including the rad-to-body seals). Same applies for any and all modifications too ;-).

Tapani

PS What are the ambient conditions in Sacramento, btw?
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  #19  
Old 03-24-2014, 09:03 AM
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Re: Strange over heating

I thought the thermostat opened by heat not a signal? All the hoses are connected properly and kink free.
Sacramento temp hasn't gotten above like 82 this year and our low was like 29 and it does it almost every day.

I've noticed if I down shift about 1/8 mile before getting off the fwy it won't over heat when I get off. And then if I keep it a gear lower on the side streets it won't over heat till lm pulling into my driveway so about 30 min of driving.
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#1 1994 Ls ebony parts car-rip
#2 1994 L laguna blue - sold
#3 1992 Lsi pearl white - sold
#4 1992 Lsi pearl white -Ate two engines - Rip
#5 1994 L Laguna Blue fwd - Now Awd and manual - 03 wrx 5mt - 18's stern warp st4s - totaled hit a tree
#6 1992 Lsi custom orange parts car
#7 1992 Lsi green 4.44 swap. Currently for sale
#8 1992 Lsi custom pearl white. Project car... sold
#9 1992 Teal 4.44 swapped... sold
#10 1995 Laguna Blue. Sti 19 wheels,
#11 1994 Laguna Blue. Came with #10 engine and trans are out but plan to put it back on the road. Willing to sell it at any time! 😂
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  #20  
Old 03-24-2014, 09:52 AM
Tapani Tapani is offline
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Re: Strange over heating

Quote:
Originally Posted by stiguy View Post
I thought the thermostat opened by heat not a signal?
Yes :-), but the flow from the bypass circuits goes to downstream side of the thermostat and forms "a signal" flow for the wax pellet, i.e. when the temp of engine (water pump) inlet (at this stage mostly bypass only) reaches the temp at which the thermostat is set to start to open it will. Then it mixes in the cold flow from the rad exit and starts to control the engine inlet. In more traditional systems the engine exit temp is controlled.

Your rad may have deposits internally causing a dramatic decrease in heat rejection capacity (heat transfer) or your fans may not operate resulting in the same - but for a different reason - lack of air flow across the rad.

Does all this happen if yo have your AC on?

Have you tried to listen for bubbling is the reservoir (whn not spitting and overheating)?

/T
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  #21  
Old 03-25-2014, 12:52 AM
Chucksta Chucksta is offline
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Re: Strange over heating

Ummm... I've read what you posted, gave it some thoughts, I looked at the FSM, goggled.. searched.. and thought.. and this is all I could come up with..


Just FYI..
Most of what I know about fluid dynamics comes from dealing with my swimming pool

But anyways..

As that the bypass line feeds the thermostat, that also means the bypass circuit and rad feed into the water pump intake, which is blind as to the source of coolant. Any fluid will flow along the path of least resistance, that means that if the rad is not flowing properly, the intake to the water pump will draw more coolant from the bypass line than normal. The position of the thermostat in the engine ( at the intake to the water pump, as opposed to the block / head exit ), and the bypass circuit, as designed work just fine, but will not tolerate blockages in any aspect of flow. From that you must keep the revs up, would seem to indicate, to me, that the additional flow through the system, caused by the higher RPM / pressure from the pump, stops localized boiling.... until you're at idle in your driveway..

As I've noticed from reading other posts in this forum, the failure of the head gasket on these engines can be hard to spot. Traditionally, a head gasket failure is usually fairly easy to spot... white smoke out the exhaust, difference in compression between two adjoining cylinders, coolant loss, etc., However, it would seem, that an SVX engine can have a head gasket problem that is not so readily apparent. And therefore, must be definitively ruled out before looking elsewhere in finding an issue, especially when it comes to a cooling problem.

I do have one question... Did the problem begin with a bang? Or, did it slowly begin to manifest itself... And if so, over what time frame?

Just as an observational note.. I have a temp gauge with no "dead zone".. and I've reconciled the gauge against the ECU readings with an OBD 2 reader. I've watched closely how the cooling system reacts to load, road speed and ambient temperature. I have no idea how old the rad in mine is ( it's a 97).. At 0 C ( 32 F ) it will stay at the thermostat opening point and not budge at anything over 40 MPH ( 75 KM/H ) ... below that, it might rise a bit, but not much. Say for example, at a light, it slowly rises towards the fan turn on point, how quickly it will return from a higher temp to it's base point is entirely dependent on road speed.. If It's at almost at the point of turning on the fans, and I hit the freeway, it's less than 30 seconds to drop it back to 185 F. I tried revving it ( locked in a lower gear or held them longer while driving / accelerating ), and couldn't see any difference in the temperature changes. I do have the rad surround installed, and the under engine shroud / pan installed..

Don't know if that helps at all.... but best of luck!!
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  #22  
Old 03-25-2014, 03:13 AM
Tapani Tapani is offline
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Re: Strange over heating

Quote:
Originally Posted by Chucksta View Post
As that the bypass line feeds the thermostat, that also means the bypass circuit and rad feed into the water pump intake, which is blind as to the source of coolant. Any fluid will flow along the path of least resistance, that means that if the rad is not flowing properly, the intake to the water pump will draw more coolant from the bypass line than normal. The position of the thermostat in the engine ( at the intake to the water pump, as opposed to the block / head exit ), and the bypass circuit, as designed work just fine, but will not tolerate blockages in any aspect of flow.
Yes, the rad pressure drop (resistance to flow) must be low enough so that it will not significantly restrict the flow when the thermostat is fully open. The thermostat is designed to be the controlling device.

If it is blocked or if it can not transfer the heat to the airflow then you end up increasing the engine inlet temp and thus causing boiling when the engine rejects the heat produced to the coolant.

It's either a coolant flow restriction, an insulating layer inside the rad (reduced heat transfer) or reduced airflow (fans, rad/body seals, etc).

Or you have a head gasket issue and open surgery is required.

/T

Last edited by Tapani; 03-25-2014 at 03:15 AM.
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  #23  
Old 04-02-2014, 10:01 AM
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major7venth major7venth is offline
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Re: Strange over heating

When at operating temp.are the fans running? If temp. Gauge is above half, its over heating.sounds like you've done everything else possible, pressure check the rad.and no steam from the exhaust smelling like coolant?
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  #24  
Old 04-15-2014, 08:58 AM
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Re: Strange over heating

Yaaaay new radiator was the fix! $136 on ebay
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#1 1994 Ls ebony parts car-rip
#2 1994 L laguna blue - sold
#3 1992 Lsi pearl white - sold
#4 1992 Lsi pearl white -Ate two engines - Rip
#5 1994 L Laguna Blue fwd - Now Awd and manual - 03 wrx 5mt - 18's stern warp st4s - totaled hit a tree
#6 1992 Lsi custom orange parts car
#7 1992 Lsi green 4.44 swap. Currently for sale
#8 1992 Lsi custom pearl white. Project car... sold
#9 1992 Teal 4.44 swapped... sold
#10 1995 Laguna Blue. Sti 19 wheels,
#11 1994 Laguna Blue. Came with #10 engine and trans are out but plan to put it back on the road. Willing to sell it at any time! 😂
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  #25  
Old 04-15-2014, 08:55 PM
Tapani Tapani is offline
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Re: Strange over heating

Good job !

Did you look into the old one? What was the problem?

/T
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  #26  
Old 04-15-2014, 11:41 PM
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Re: Strange over heating

Yeah I took it into a radiator shop and they looked at it and said it was plugged.
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#1 1994 Ls ebony parts car-rip
#2 1994 L laguna blue - sold
#3 1992 Lsi pearl white - sold
#4 1992 Lsi pearl white -Ate two engines - Rip
#5 1994 L Laguna Blue fwd - Now Awd and manual - 03 wrx 5mt - 18's stern warp st4s - totaled hit a tree
#6 1992 Lsi custom orange parts car
#7 1992 Lsi green 4.44 swap. Currently for sale
#8 1992 Lsi custom pearl white. Project car... sold
#9 1992 Teal 4.44 swapped... sold
#10 1995 Laguna Blue. Sti 19 wheels,
#11 1994 Laguna Blue. Came with #10 engine and trans are out but plan to put it back on the road. Willing to sell it at any time! 😂
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  #27  
Old 04-16-2014, 03:07 AM
Tapani Tapani is offline
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Re: Strange over heating

Did you get your system properly cleaned? If not.....

What ever it is (probably calcium based stuff from tap water) you have it everywhere in the system.

All your engine water jackets have it. Your heater core has it.

Naturally it will have a substancial effect on heat transfer from engine castings to the coolant and from coolant to the heater core to the cabin air.

The deposits in the water jackets will make your engine parts run hot w/o you noticing it (only coolant temp is controlled).

/T
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  #28  
Old 04-20-2014, 01:24 PM
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Re: Strange over heating

No I haven't how do you go about doing that?
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#1 1994 Ls ebony parts car-rip
#2 1994 L laguna blue - sold
#3 1992 Lsi pearl white - sold
#4 1992 Lsi pearl white -Ate two engines - Rip
#5 1994 L Laguna Blue fwd - Now Awd and manual - 03 wrx 5mt - 18's stern warp st4s - totaled hit a tree
#6 1992 Lsi custom orange parts car
#7 1992 Lsi green 4.44 swap. Currently for sale
#8 1992 Lsi custom pearl white. Project car... sold
#9 1992 Teal 4.44 swapped... sold
#10 1995 Laguna Blue. Sti 19 wheels,
#11 1994 Laguna Blue. Came with #10 engine and trans are out but plan to put it back on the road. Willing to sell it at any time! 😂
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  #29  
Old 04-20-2014, 01:34 PM
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Re: Strange over heating

Okay so now with a new SILIA radiator in it runs good...... But now after a drive or two it starts to do the same thing again . But I noticed this time it's cus it's low on water so I thought well maybe air was in the system so I filled it up a few times. But then it started spewing water out the resavor. So I did this test.

I filled up the radiator when it was cold. Emptied the resistor compleatly. Drove it home 15miles. Just started to over heat when I got home. The next day I opened the radiator it was low on coolant. Checked the resivor it was full. So I poured what was in the resavor into the radiator and it filled it up perfectly.

So I know I'm not "losing" coolant it's still there just not in the right place. My thoughts bad radiator cap? Not letting pressure out and the coolant from the resivor back into the radiator?

Any more thoughts?
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#1 1994 Ls ebony parts car-rip
#2 1994 L laguna blue - sold
#3 1992 Lsi pearl white - sold
#4 1992 Lsi pearl white -Ate two engines - Rip
#5 1994 L Laguna Blue fwd - Now Awd and manual - 03 wrx 5mt - 18's stern warp st4s - totaled hit a tree
#6 1992 Lsi custom orange parts car
#7 1992 Lsi green 4.44 swap. Currently for sale
#8 1992 Lsi custom pearl white. Project car... sold
#9 1992 Teal 4.44 swapped... sold
#10 1995 Laguna Blue. Sti 19 wheels,
#11 1994 Laguna Blue. Came with #10 engine and trans are out but plan to put it back on the road. Willing to sell it at any time! 😂
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  #30  
Old 04-20-2014, 01:50 PM
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Wikedjuggalo Wikedjuggalo is offline
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Re: Strange over heating

Quote:
Originally Posted by stiguy View Post
Okay so now with a new SILIA radiator in it runs good...... But now after a drive or two it starts to do the same thing again . But I noticed this time it's cus it's low on water so I thought well maybe air was in the system so I filled it up a few times. But then it started spewing water out the resavor. So I did this test.

I filled up the radiator when it was cold. Emptied the resistor compleatly. Drove it home 15miles. Just started to over heat when I got home. The next day I opened the radiator it was low on coolant. Checked the resivor it was full. So I poured what was in the resavor into the radiator and it filled it up perfectly.

So I know I'm not "losing" coolant it's still there just not in the right place. My thoughts bad radiator cap? Not letting pressure out and the coolant from the resivor back into the radiator?

Any more thoughts?
Go to a local auto parts store and get the loaner tool to check the cap. Make sure you got all the air bubbles out. I suggest raising the front of the car so the radiator is the highest point. Heat on high and fill as needed.

If the cap comes back good, bleed the system and you still lose coolant / overheat it will probably be what you don't want it to be. When was the water pump last done?
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