[2twin89s]

Ok, I have been through the bhg on one of my supras. Now my wifes is filling the overflow. Has never overheated, no gurgle, passed the block test. I changed the rad cap, checked thermo, was stuck shut, replaced that, oil looks clean, exhaust seems normal. No power loss. After I replaced the thermo drove about 8 miles check overflow was not full. Checked after cool down still not full. Drove again now its full. My next check is a compression check. Is there anything else I am missing?

 

[grankor]

When the engine is at norm running temp, take the rad cap off and see if the coolant flows.

-checking to make sure pump is working properly.

 

[suprafly1986]

Do you mean it was not full when it was cold but it was full when it was hot? Thats normal

 

[2twin89s]

With the rad cap off the collant will push itself out of radiator. After the overflow gets full it stays full. But it never overflows. It has about a 1/2 and inch left before its full. I did squezze the top rad hose when it was at full temp and did feel a "surge". Thanks for the replys.

 

[Ryan_Tex]

that's what it sounded like. Why not remove the radiator cap and bring to full operating temp and see what happens. Lose some of the built up air in the system although prolonged bubbles could mean head gasket

 

[2twin89s]

I think I am gonna start with the pump this weekend. I went out and checked the bottle. Coollant is cold in bottle but still to full. Top rad hose is empty. I remember in my other supra before the bgh I had the gurrgle in the dash. This one has no gurgle. I pray no bhg, I dont need that right now. Thanks for all the suggestions. Gotta love our MKIII's!

 

[young blood]

I had a BHG, but I fix it last summer, the engine kept overheating. I changed almost everything, temp gauge, radcap, waterpump and fancluch, burped the system a few times and it still overheated. I'm still driving it in the winter, and it hasn't overheated once. want should I do before this summer?

 

[MKIVpowered]

2twin89s,

So when you drive your car fills the overflow but it doesnt suck it back in when it cools down? hince the radiator stays empty. If so I woudl start with the water pump and the fact that it isnt circulating good. Also it could be the fan clutch or fans arent cooling good enough. Start with the pump.

Will

 

[2twin89s]

Thanks for all the help everyone. I am going to replace the pump this weekend. I did notice there is now a squeeling noise close to the pump. I will post my findings after I chnage the pump.

 

[suprasteve]

first thing to do is fit a new rad cap
i have seen it soooooo many times
ppl change all the expensive bits only to find it was that dam rad cap

 

[MKIIINA]

that water sound in the dash was trapped air in cooling system and is a simple fix check the sogi site. do u have to keep refilling the bottle or its just showing low? it could be leaking through a pipe on the back of the engine very slowly and it only leaks when you have the car running. same thing happened to me and took me forever to find the damn thing... g luck and peace

 

[2twin89s]

Well looks like BHG. Checked the water pump all flowing great. So I purged the system got all the air out and the next day drove to work. Checked the over flow and it seemed to be at the normal level. After about 3 days of driving its almost full again. So after I got home today I pulled the oil cap and looked inside.. no brownish gunk but the cap smelled like gas. So I would say it did the same thing as my other supra hg went on the gas side. If I am wrong please correct me before I jump into this venture. This time I going to do it myself. I have already started reading all the threads on doing hg. I am going to order the metal one and the new ARP head bolts. Thanks for all the advise everyone. This forum is full of a bunch of great Supra owners.

 

[chevyeater-on-sf]

first thing to do is fit a new rad cap
i have seen it soooooo many times
ppl change all the expensive bits only to find it was that dam rad cap

I concur. Change the 5 dollar part first. The only two things that could cause your problem are a radiator cap or a BHG.

 

[GrimJack]

AND check the overflow tank siphon tube!

If you get a crack near the top of the siphon, it will still pour coolant into the overflow tank when hot, but it will suck in air from the crack when cooling down.

PS: I'd do the full gamut of tests before tearing off the head, unless you *want* to do a head gasket job just for fun. Compression, leakdown, you've already done the block test, see what those net you first.

Suprasteve is right on the money, though. Start with the cheap fixes!

 

[2twin89s]

I have replaced the cap and the thermo. I am pretty sure the coolant side is sealed because when I pulled the cap when it was cold it released some pressure. I will check the hose in the overflow. Its also now rough idling almost feels like a missfire at times like if I go out and car sits for 15 or 20 min then start up again it idles realy ruff. The last time it died 3 times before it stayed running. I know they call that heat soke when its really hot. But I will definatly do all the easy diags before pulling the head. Thanks everyone.

 

[GrimJack]

It's easy to eliminate heat soak, just let it cool completely. Coolant in the cylinders will stay there after the car cools, and make it difficult to start even the next day. Heat soak will be gone after the engine bay cools off sufficiently.

 

[aaron300]

Its also now rough idling almost feels like a missfire at times like if I go out and car sits for 15 or 20 min then start up again it idles realy ruff. The last time it died 3 times before it stayed running.

Pull the plug wires and check the boots for coolant. You could have freeze plugs in you head that have come unsealed and are allowing small amounts of coolant to leak out under pressure. They're on the top of the head, so the coolant that sprays out puddles up in the plug wells. It will cause the car to misfire(especailly in the 1900-2200 RPM range) and idle rough. Freeze plugs can be re-sealed pretty cheap. If you find that your plug wires have been sitting in coolant for any period of time, ditch them. It degrades the insulating capabilty of the wires, and you will end up with more misfiring problems. Hopefully this is the problem and not a cracked head or blown gasket. Good luck.