overheating m20 troubleshooting (updated)

[Pantless Spency]

How long have you had this car?

about a month or so

[Pantless Spency]

updated original post

[Pantless Spency]

bump for help.

[urbancynic]

Have you tried simply smacking or tapping the gauge when it starts heating up?

Or how about holding pressure on the gauge face?

Seems stupid, but if there's an electrical issue with the cluster, particularly the temp gauge, then it will read that its overheating when it isn't actually overheating.

If your fan clutch is good, fan switches are good and fan kicks on, lower radiator hose gets warm when gauge reads about half way, then I would start looking at something electrical with the cluster. It may just be that simple and stupid.

Another idea is to get yourself a digital thermometer and see exactly what the temps are of the hoses and other various areas coolant passes through.

[Pantless Spency]

the gauge was a little wacky at first but now its spot on. no bouncing nothing and when it reads hot, i open the hood up, go give the coolant reservoir a feel and its incredibly hot to the touch, and it's over heated on the side of a freeway on me before lol.

[stoker1010]

Other things to try.

1. Is the radiator in good condition. ie. not blocked and the cooling fins not crumbly (allow good heat transfer)

2. May have silicate dropout (green jelly like substance) from old coolant or mixing different coolants that may be causing blockages in the radiator or head. Could try giving it a flush out with an alkaline salt flushing product?

[Pantless Spency]

soooooo it was running hot for a while and just recently had some sort of "burp".
no more over heating yay! but then some lights came on regarding my oil. went to check the oil and on the dipstick theres a tiny bit of creamy mayonaise like residue..... thinking i have a blown head :( what does r3v think?.
if it is truly blown i have two options, buy a new m20 on the cheap, or buy a head gasket kit and get to town on my m20. i have no experience doing head gasket work what so ever.... also another question, if i were to buy a non ETA m20 to replace my ETA m20, such as the newer 2.5L engine would it be a direct bolt in and hook up? or what would i have to change with that swap? the e30 is kickin my ass boys. need some help haha.

[urbancynic]

Sounds like a head gasket to me. Pull the head and take it to a machine shop to be checked out to make sure it isn't cracked or warped.

If it is ok go ahead and use it. Make sure to flush the entire cooling system. Also, order new head bolts.

Make sure you have a bentley manual

[blackhawkimpact]

I have an "I" head for sale. Need a rocker arm though.

[Pantless Spency]

^ whats the whole deal with the 885 head on the 2.7l? i don't understand exactly how it works. and how much different would the power be, would it be more powerful then the 2.5l?

[Pantless Spency]

hey guys i have a question, an m20 eta from an 85 will go straight into an eta m20 86 chassis and wire straight up with no hassles correct? i found a lead on a an 85 2.7 eta with new rad. brand new engine stand and new engine mounts + other goodies for around 300. and no blown head gasket which is great haha. anyone know if its a direct bolt in and wire up?

[Danny]

hey guys i have a question, an m20 eta from an 85 will go straight into an eta m20 86 chassis and wire straight up with no hassles correct? i found a lead on a an 85 2.7 eta with new rad. brand new engine stand and new engine mounts + other goodies for around 300. and no blown head gasket which is great haha. anyone know if its a direct bolt in and wire up?

Yeah but it won't technically be smog legal.

[Pantless Spency]

Yeah but it won't technically be smog legal.

:( I'm just going to try my best to replace the gasket on mine

[urbancynic]

I hear the head gasket on the m20 is easy. Its the head gasket on the m50 that is difficult.

Certainly doesn't look hard to do the head gasket on an eta anyways.