Engine running hot?

[Accufab]

Some of our customers have experienced the GT engines running hot. This is most prevelent when they are running the car hard, such as in a road racing environment. This problem is related to the engine not getting efficient coolant circulation. We have had several cars on the chassis dyno and noticed an interesting little issue, one that is almost impossible to see except on the dyno or a chassis lift (so you could view it from the underneath). The water pump is so efficient, it creates a partial vacuum causing the radiator hoses to suck closed. This starts at as low as 3500 RPM and by 6000 RPM, the hoses are completley (almost) closed off. No wonder these things are running hot.

John Mihovetz has had some stainless steel springs made, springs that are the exact inside diameter of the hoses, to fit inside the hose to keep them open at all times. The inlet hoses that are effected are the lower radiator hose in the front, and the one at the rear too, the one near the engine. This is an easy fix and John tells me that he will offer these hoses as a regular Accufab item within a day or two. Once installed inside the hose, you can stand on them with all your weight and they won't cave in.

We are working on posting a video of exactly what happens to the hoses as rpm increases. The installation is quite a task though because it requires the removal of the front, mid and rear belly pans to get access to the hoses.

 

[analogdesigner]

Nice work guys! They are even stainless steel. I'll call soon and order a set.

Jay
GTsaver

 

[Fubar]

Just a few questions:
1) Is there a concern about the springs breaking down over time?
2) Are you fairly certain that installing this fix doesn't create new stress on other hose sections?
3) Any idea why this doesn't affect all cars?

This has been a nagging issue for my car. I'm glad to see you guys have a fix in the works.

 

[andymlow]

I'm very interested as my car is affected, but I for one would love to see some real world numbers that prove this is the fix. Show me pre and post flow rates or pre and post coolant temps etc. Thanks for effort on behalf of all the "hot" GT's out there.

Andy

 

[Accufab]

1. The springs are stainless steel so there won't be any corrosion issues over time.

2. I am not certain about stresses on other hoses, but we will address them if they arise. Certainly can't be worse than no coolant flow above 5000 rpm's.

3. It does effect all cars from the first produced to the last. It doesn't appear often because most people don't drive the cars that long at sustained rpms unless on the track.


Thanks,

John Mihovetz

 

[isaakgt]

Looks good to me. This is how they manufactured radiator hose not too many years ago. Why did they stop using springs? $$$$$$$? :shrug

 

[ViperJoe]

How are the springs secured in the hoses to prevent migration, possibly into the H2O pump?

 

[nota4re]

The springs can't fit inside the neck of the attach points.

John, very nice job. It is the second time (at least) you have come to the rescue of GT owners!!! (Great job on the insight/design of the axle bolts too !!)

 

[Kingman]

Is it just the spring or the hose with the spring already situated?

That looks like it would be quite a bit of work to wiggle them through without screwin up the spring.

 

[isaakgt]

Is it just the spring or the hose with the spring already situated?

That looks like it would be quite a bit of work to wiggle them through without screwin up the spring.

The springs slide into the hose. Springs have been used in radiator hoses for many years in many applications.:wink

 

[analogdesigner]

German fit

The trick to installing them is to rotate them clock-wise as to making the spring decrease in diameter as you work it into the hose. It looks as it should be a German fit!. Jay Gtsaver

 

[BlackICE]

Does anyone know what is involved with installing the hoses. The hose near on the water pump look easy, but the one connecting to the radiator may be a pain in the as-!

Which hose is more likely to collapse?

 

[ChipBeck]

Easy

Which hose is more likely to collapse?

The one you didn't put the spring in.
Chip

 

[BlackICE]

The one you didn't put the spring in.
Chip

Gee, Chip you get an A in the class!

:thumbsup

 

[PL510*Jeff]

Hose colapse

I have had my GT on the track more than a few times.

After scaring the poo poo out of me on the first "operation" of the coolant tank cap, I now come in after a max of 45 minutes of hard running.

Temp is bout 235. Let it cool for about 15 minutes and the out to play again.

Please put me on the Order List for your spring/hose upgrade.

There was "some" discussion at the Rally II, over a few beers, that in addition to the main hose closing off, this may also be occurring in the smaller transfer hoses from the rad back to the engine compartment. These are really hidden from view, so verifying if they are part of the solution to the higher temp's some GT's have, will be more difficult.

 

[analogdesigner]

Does anyone know what is involved with installing the hoses. The hose near on the water pump look easy, but the one connecting to the radiator may be a pain in the as-!

Which hose is more likely to collapse?

All things equal, the longer hose will give first.

Jay
GTsaver

 

[Fubar]

All things equal, the longer hose will give first.

Jay
GTsaver

How about the hoses that run from the front to the back? Are they potential problems? …might as well do it all at once.

 

[BlackICE]

How about the hoses that run from the front to the back? Are they potential problems? …might as well do it all at once.

I don't know, but I am guessing that is a long metal tube.

 

[Fubar]

I'm sure all of you guys have seen this but I just found it so...

http://www.roushind.com/news_downloads/tech_papers/2004-01-1252.pdf

good stuff

 

[cobrar1339]

When they get the video posted you should have a better idea of what is happening. Originally, the one hose was closing off at the engine. When that hose was fixed, the problem transfered to the front of the car. Some of you mentioned that as a possiblility. Your thoughts are correct. Then that hose was fixed. After this, no other problems showed up or they would have been fixed as well.

Not many of us would have a GT on a rack with all the gear removed to view it properly looking for this. Running the engine high enough, over and over to see and doucument the problem. Then put apply a fix and test again. Only to find another problem and fix yet again.


I for one, believe John / Accufab has this figured out. They have been working on this for several months.

Thanks to the Accufab Team for yet another part aimed at improving the reliability of the GT.:thumbsup